Recorrido en zigzag (o diagonal) de Matrix – Part 1

Dada una array 2D, imprima todos los elementos de la array dada en orden diagonal. Por ejemplo, considere la siguiente array de entrada de 5 X 4.  

Ejemplo:

1     2     3     4
5     6     7     8
9    10    11    12
13    14    15    16
17    18    19    20

La impresión diagonal de la array anterior es

1
5 2
9 6 3
13 10 7 4
17 14 11 8
18 15 12
19 16
20

Otro ejemplo

diagonal-matrix

Le recomendamos encarecidamente que haga clic aquí y lo practique antes de pasar a la solución.

A continuación se muestra el código para la impresión en diagonal.
La impresión diagonal de una array dada «array [ROW] [COL]» siempre tiene «ROW + COL – 1» líneas en la salida. 

Implementación:

C++

// C++ program to print all elements
// of given matrix in diagonal order
#include <bits/stdc++.h>
using namespace std;
 
#define ROW 5
#define COL 4
 
// A utility function to find min
// of two integers
int minu(int a, int b)
{
    return (a < b) ? a : b;
}
 
// A utility function to find min
// of three integers
int min(int a, int b, int c)
{
    return minu(minu(a, b), c);
}
 
// A utility function to find
// max of two integers
int max(int a, int b)
{
    return (a > b) ? a : b;
}
 
// The main function that prints given
// matrix in diagonal order
void diagonalOrder(int matrix[][COL])
{
     
    // There will be ROW+COL-1 lines
    // in the output
    for(int line = 1;
            line <= (ROW + COL - 1);
            line++)
    {
         
        /* Get column index of the first element
           in this line of output.
           The index is 0 for first ROW lines and
           line - ROW for remaining lines  */
        int start_col =  max(0, line - ROW);
 
        /* Get count of elements in this line. The
           count of elements is equal to minimum of
           line number, COL-start_col and ROW */
         int count = min(line, (COL - start_col), ROW);
 
        /* Print elements of this line */
        for(int j = 0; j < count; j++)
            cout << setw(5) <<
            matrix[minu(ROW, line) - j - 1][start_col + j];
 
        /* Print elements of next
           diagonal on next line */
        cout << "\n";
    }
}
 
// Utility function to print a matrix
void printMatrix(int matrix[ROW][COL])
{
    for(int i = 0; i < ROW; i++)
    {
        for(int j = 0; j < COL; j++)
            cout << setw(5) << matrix[i][j];
             
        cout << "\n";
    }
}
 
// Driver code
int main()
{
    int M[ROW][COL] = { { 1, 2, 3, 4 },
                        { 5, 6, 7, 8 },
                        { 9, 10, 11, 12 },
                        { 13, 14, 15, 16 },
                        { 17, 18, 19, 20 },};
    cout << "Given matrix is " << endl;
    printMatrix(M);
 
    cout << "\nDiagonal printing of matrix is " << endl;
    diagonalOrder(M);
    return 0;
}
 
// This code is contributed by shubhamsingh10

C

// C program to print all elements
// of given matrix in diagonal order
#include <stdlib.h>
 
#define ROW 5
#define COL 4
 
// A utility function to find min of two integers
int minu(int a, int b)
{ return (a < b)? a: b; }
 
// A utility function to find min of three integers
int min(int a, int b, int c)
{ return minu(minu(a, b), c);}
 
// A utility function to find max of two integers
int max(int a, int b)
{ return (a > b)? a: b; }
 
// The main function that prints given matrix in
// diagonal order
void diagonalOrder(int matrix[][COL])
{
    // There will be ROW+COL-1 lines in the output
    for (int line=1; line<=(ROW + COL -1); line++)
    {
        /* Get column index of the first element
           in this line of output.
           The index is 0 for first ROW lines and
           line - ROW for remaining lines  */
        int start_col =  max(0, line-ROW);
 
        /* Get count of elements in this line. The
           count of elements is equal to minimum of
           line number, COL-start_col and ROW */
         int count = min(line, (COL-start_col), ROW);
 
        /* Print elements of this line */
        for (int j=0; j<count; j++)
            printf("%5d ",
                   matrix[minu(ROW, line)-j-1][start_col+j]);
 
        /* Print elements of next diagonal on next line */
        printf("\n");
    }
}
 
// Utility function to print a matrix
void printMatrix(int matrix[ROW][COL])
{
    for (int i=0; i< ROW; i++)
    {
        for (int j=0; j<COL; j++)
            printf("%5d ", matrix[i][j]);
        printf("\n");
    }
}
 
// Driver code
int main()
{
    int M[ROW][COL] = {{1, 2, 3, 4},
                       {5, 6, 7, 8},
                       {9, 10, 11, 12},
                       {13, 14, 15, 16},
                       {17, 18, 19, 20},
                      };
    printf ("Given matrix is \n");
    printMatrix(M);
 
    printf ("\nDiagonal printing of matrix is \n");
    diagonalOrder(M);
    return 0;
}

Java

// Java program to print all elements
// of given matrix in diagonal order
class GFG {
    static final int ROW = 5;
    static final int COL = 4;
 
    // A utility function to find min
    // of two integers
    static int min(int a, int b)
    {
        return (a < b) ? a : b;
    }
 
    // A utility function to find min
    // of three integers
    static int min(int a, int b, int c)
    {
        return min(min(a, b), c);
    }
 
    // A utility function to find max
    // of two integers
    static int max(int a, int b)
    {
         return (a > b) ? a : b;
    }
 
    // The main function that prints given
    // matrix in diagonal order
    static void diagonalOrder(int matrix[][])
    {
 
        // There will be ROW+COL-1 lines in the output
        for (int line = 1;
             line <= (ROW + COL - 1);
             line++) {
 
            // Get column index of the first
            // element in this line of output.
            // The index is 0 for first ROW
            // lines and line - ROW for remaining lines
            int start_col = max(0, line - ROW);
 
            // Get count of elements in this line.
            // The count of elements is equal to
            // minimum of line number, COL-start_col and ROW
            int count = min(line, (COL - start_col),
                            ROW);
 
            // Print elements of this line
            for (int j = 0; j < count; j++)
                System.out.print(matrix[min(ROW, line)
                                        - j- 1][start_col + j]
                                 + " ");
 
            // Print elements of next diagonal on next line
            System.out.println();
        }
    }
 
    // Utility function to print a matrix
    static void printMatrix(int matrix[][])
    {
        for (int i = 0; i < ROW; i++)
        {
            for (int j = 0; j < COL; j++)
                System.out.print(matrix[i][j] + " ");
            System.out.print("\n");
        }
    }
 
    // Driver code
    public static void main(String[] args)
    {
        int M[][] = {
            { 1, 2, 3, 4 },     { 5, 6, 7, 8 },
            { 9, 10, 11, 12 },  { 13, 14, 15, 16 },
            { 17, 18, 19, 20 },
        };
        System.out.print("Given matrix is \n");
        printMatrix(M);
 
        System.out.print(
            "\nDiagonal printing of matrix is \n");
        diagonalOrder(M);
    }
}
// This code is contributed by Anant Agarwal.

Python3

# Python3 program to print all elements
# of given matrix in diagonal order
ROW = 5
COL = 4
 
# Main function that prints given
# matrix in diagonal order
 
 
def diagonalOrder(matrix):
 
    # There will be ROW+COL-1 lines in the output
    for line in range(1, (ROW + COL)):
        # Get column index of the first element
        # in this line of output. The index is 0
        # for first ROW lines and line - ROW for
        # remaining lines
        start_col = max(0, line - ROW)
 
        # Get count of elements in this line.
        # The count of elements is equal to
        # minimum of line number, COL-start_col and ROW
        count = min(line, (COL - start_col), ROW)
 
        # Print elements of this line
        for j in range(0, count):
            print(matrix[min(ROW, line) - j - 1]
                        [start_col + j], end="\t")
 
        print()
 
 
# Utility function to print a matrix
def printMatrix(matrix):
    for i in range(0, ROW):
        for j in range(0, COL):
            print(matrix[i][j], end="\t")
 
        print()
 
 
# Driver Code
M = [[1, 2, 3, 4],
     [5, 6, 7, 8],
     [9, 10, 11, 12],
     [13, 14, 15, 16],
     [17, 18, 19, 20]]
print("Given matrix is ")
printMatrix(M)
 
print("\nDiagonal printing of matrix is ")
diagonalOrder(M)
 
# This code is contributed by Nikita Tiwari.

C#

// C# program to print all elements
// of given matrix in diagonal order
using System;
using static System.Math;
 
class GFG {
 
    static int ROW = 5;
    static int COL = 4;
 
    // The main function that prints given
    // matrix in diagonal order
    static void diagonalOrder(int[, ] matrix)
    {
 
        // There will be ROW+COL-1 lines in the output
        for (int line = 1;
             line <= (ROW + COL - 1);
             line++) {
 
            // Get column index of the first element
            // in this line of output.The index is 0
            // for first ROW lines and line - ROW for
            // remaining lines
            int start_col = Max(0, line - ROW);
 
            // Get count of elements in this line. The
            // count of elements is equal to minimum of
            // line number, COL-start_col and ROW
            int count = Min(line, Math.Min((COL - start_col), ROW));
 
            // Print elements of this line
            for (int j = 0; j < count; j++)
                Console.Write(matrix[Min(ROW, line) - j - 1, start_col + j] + " ");
 
            // Print elements of next diagonal
            // on next line
            Console.WriteLine();
        }
    }
 
    // Utility function to print a matrix
    static void printMatrix(int[, ] matrix)
    {
        for (int i = 0; i < ROW; i++)
        {
            for (int j = 0; j < COL; j++)
                Console.Write(matrix[i, j] + " ");
 
            Console.WriteLine("\n");
        }
    }
 
    // Driver code
    public static void Main()
    {
        int[, ] M = { { 1, 2, 3, 4 },
                      { 5, 6, 7, 8 },
                      { 9, 10, 11, 12 },
                      { 13, 14, 15, 16 },
                      { 17, 18, 19, 20 } };
 
        Console.Write("Given matrix is \n");
         
        printMatrix(M);
 
        Console.Write("\nDiagonal printing" + " of matrix is \n");
 
        diagonalOrder(M);
    }
}
 
// This code is contributed by Sam007.

PHP

<?php
// PHP Code for Zigzag (or diagonal)
// traversal of Matrix
$ROW = 5;
$COL = 4;
 
// The main function that prints
// given matrix in diagonal order
function diagonalOrder(&$matrix)
{
    global $ROW, $COL;
     
    // There will be ROW+COL-1
    // lines in the output
    for ($line = 1;
         $line <= ($ROW + $COL - 1); $line++)
    {
        /* Get column index of the first
           element in this line of output.
           The index is 0 for first ROW lines
           and line - ROW for remaining lines */
        $start_col = max(0, $line - $ROW);
 
        /* Get count of elements in this line.
           The count of elements is equal to
           minimum of line number, COL-start_col
           and ROW */
        $count = min($line, ($COL -
                     $start_col), $ROW);
 
        /* Print elements of this line */
        for ($j = 0; $j < $count; $j++)
        {
            echo $matrix[min($ROW, $line) -
                 $j - 1][$start_col + $j];
            echo "\t";
        }
 
        /* Print elements of next
           diagonal on next line */
        print("\n");
    }
}
 
// Utility function
// to print a matrix
function printMatrix(&$matrix)
{
    global $ROW, $COL;
    for ($i = 0; $i < $ROW; $i++)
    {
        for ($j = 0; $j < $COL; $j++)
        {
            echo $matrix[$i][$j] ;
            echo "\t";
        }
        print("\n");
    }
}
 
// Driver Code
$M = array(array(1, 2, 3, 4),
           array(5, 6, 7, 8),
           array(9, 10, 11, 12),
           array(13, 14, 15, 16),
           array(17, 18, 19, 20));
echo "Given matrix is \n";
printMatrix($M);
 
printf ("\nDiagonal printing " .
        "of matrix is \n");
diagonalOrder($M);
 
// This code is contributed
// by ChitraNayal
?>

Javascript

<script>
// Javascript program to print all elements
// of given matrix in diagonal order
 
let ROW = 5;
let COL = 4;
 
// A utility function to find min
    // of two integers
function min(a, b)
{
    return (a < b) ? a : b;
}
 
// A utility function to find min
    // of three integer
function _min(a, b, c)
{
    return min(min(a, b), c);
}
 
// A utility function to find max
    // of two integers
function max(a,b)
{
    return (a > b) ? a : b;
}
 
// The main function that prints given
    // matrix in diagonal order
function diagonalOrder(matrix)
{
    // There will be ROW+COL-1 lines in the output
        for (let line = 1;
             line <= (ROW + COL - 1);
             line++) {
  
            // Get column index of the first
            // element in this line of output.
            // The index is 0 for first ROW
            // lines and line - ROW for remaining lines
            let start_col = max(0, line - ROW);
  
            // Get count of elements in this line.
            // The count of elements is equal to
            // minimum of line number, COL-start_col and ROW
            let count = min(line, (COL - start_col),
                            ROW);
  
            // Print elements of this line
            for (let j = 0; j < count; j++)
                document.write(matrix[min(ROW, line)
                                        - j- 1][start_col + j]
                                 + " ");
  
            // Print elements of next diagonal on next line
            document.write("<br>");
        }
}
 
// Utility function to print a matrix
function printMatrix(matrix)
{
    for (let i = 0; i < ROW; i++)
        {
            for (let j = 0; j < COL; j++)
                document.write(matrix[i][j] + " ");
            document.write("<br>");
        }
}
 
// Driver code
let M = [[ 1, 2, 3, 4 ], [ 5, 6, 7, 8 ],
            [ 9, 10, 11, 12 ],  [ 13, 14, 15, 16 ],
            [ 17, 18, 19, 20 ]];
document.write("Given matrix is <br>");
printMatrix(M);
 
document.write(
"<br>Diagonal printing of matrix is <br>");
diagonalOrder(M);
 
// This code is contributed by ab2127
</script>
Producción

Given matrix is 
    1     2     3     4 
    5     6     7     8 
    9    10    11    12 
   13    14    15    16 
   17    18    19    20 

Diagonal printing of matrix is 
    1 
    5     2 
    9     6     3 
   13    10     7     4 
   17    14    11     8 
   18    15    12 
   19    16 
   20 

Complejidad temporal: O(fila x columna) 
Espacio auxiliar: O(1)

A continuación se muestra un método alternativo para resolver el problema anterior.

Matrix =>       1     2     3     4
                5     6     7     8
                9     10    11   12
                13    14    15   16
                17    18    19   20 
   
Observe the sequence
          1 /  2 /  3 /  4
           / 5  /  6 /  7 /  8
               /  9 / 10 / 11 / 12
                   / 13 / 14 / 15 / 16
                       / 17 / 18 / 19 / 20

Implementación:

C++

#include <bits/stdc++.h>
#define R 5
#define C 4
using namespace std;
 
bool isValid(int i, int j)
{
    if (i < 0 || i >= R
        || j >= C || j < 0)
        return false;
    return true;
}
 
void diagonalOrder(int arr[][C])
{
    /* through this for loop we choose
       each element of first column as
       starting point and print diagonal
       starting at it.
    arr[0][0], arr[1][0]....arr[R-1][0]
    are all starting points */
    for (int k = 0; k < R; k++)
    {
        cout << arr[k][0] << " ";
       
        // set row index for next point in
        // diagonal
        int i = k - 1;
        
        // set column index for next point in
        //    diagonal
        int j = 1;
 
        /* Print Diagonally upward */
        while (isValid(i, j)) {
            cout << arr[i][j] << " ";
            i--;
           
            // move in upright direction
            j++;
        }
        cout << endl;
    }
 
    /* through this for loop we choose
       each element of last row as starting
       point (except the [0][c-1] it has
       already been processed in previous
       for loop) and print diagonal starting
       at it. arr[R-1][0], arr[R-1][1]....arr[R-1][c-1]
       are all starting points
     */
 
    // Note : we start from k = 1 to C-1;
    for (int k = 1; k < C; k++)
    {
        cout << arr[R - 1][k] << " ";
       
        // set row index for next point in
        // diagonal
        int i = R - 2;
         
        // set column index for next point in
        // diagonal
        int j = k + 1;
 
        /* Print Diagonally upward */
        while (isValid(i, j))
        {
            cout << arr[i][j] << " ";
            i--;
           
            // move in upright direction
            j++;
        }
        cout << endl;
    }
}
 
// Driver Code
int main()
{
 
    int arr[][C] = {
        { 1, 2, 3, 4 },    
        { 5, 6, 7, 8 },
        { 9, 10, 11, 12 }, 
        { 13, 14, 15, 16 },
        { 17, 18, 19, 20 },
    };
    diagonalOrder(arr);
    return 0;
}

Java

// JAVA Code for Zigzag (or diagonal)
// traversal of Matrix
 
class GFG {
 
    public static int R, C;
 
    private static void diagonalOrder(int[][] arr)
    {
 
        /* through this for loop we choose each
        element of first column as starting point
        and print diagonal starting at it. arr[0][0],
        arr[1][0]....arr[R-1][0] are all starting points */
        for (int k = 0; k < R; k++) {
            System.out.print(arr[k][0] + " ");
 
            // set row index for next
            // point in diagonal
            int i = k - 1;
           
            //  set column index for
            // next point in diagonal
            int j = 1;
 
            /* Print Diagonally upward */
            while (isValid(i, j))
            {
                System.out.print(arr[i][j] + " ");
 
                i--;
                
                // move in upright direction
                j++;
            }
 
            System.out.println("");
        }
 
        /* through this for loop we choose each element
           of last row as starting point (except the
           [0][c-1] it has already been processed in
           previous for loop) and print diagonal
           starting at it. arr[R-1][0], arr[R-1][1]....
           arr[R-1][c-1] are all starting points */
 
        // Note : we start from k = 1 to C-1;
        for (int k = 1; k < C; k++) {
            System.out.print(arr[R - 1][k] + " ");
 
            // set row index for next
            // point in diagonal
            int i = R - 2;
           
            // set column index for
            // next point in diagonal
            int j = k + 1;
 
            /* Print Diagonally upward */
            while (isValid(i, j))
            {
                System.out.print(arr[i][j] + " ");
 
                // move in upright direction
                i--;
                j++;
            }
 
            System.out.println("");
        }
    }
 
    public static boolean isValid(int i, int j)
    {
        if (i < 0 || i >= R
            || j >= C || j < 0)
            return false;
        return true;
    }
 
    // Driver code
    public static void main(String[] args)
    {
        int arr[][] = {
            { 1, 2, 3, 4 },    
            { 5, 6, 7, 8 },
            { 9, 10, 11, 12 }, 
            { 13, 14, 15, 16 },
            { 17, 18, 19, 20 },
        };
 
        R = arr.length;
        C = arr[0].length;
 
        // Function call
        diagonalOrder(arr);
    }
}
 
// This code is contributed by Arnav Kr. Mandal.

Python3

# Python3 program to print all elements
# of given matrix in diagonal order
R = 5
C = 4
 
 
def isValid(i, j):
    if (i < 0 or i >= R or j >= C or j < 0):
        return False
    return True
 
 
def diagonalOrder(arr):
 
    # through this for loop we choose each element
    # of first column as starting point and print
    # diagonal starting at it.
    # arr[0][0], arr[1][0]....arr[R-1][0]
    # are all starting points
    for k in range(0, R):
        print(arr[k][0], end="  ")
 
        # set row index for next point in diagonal
        i = k - 1
 
        # set column index for next point in diagonal
        j = 1
 
        # Print Diagonally upward
        while (isValid(i, j)):
            print(arr[i][j], end="  ")
            i -= 1
            j += 1  # move in upright direction
 
        print()
 
    # Through this for loop we choose each
    # element of last row as starting point
    # (except the [0][c-1] it has already been
    # processed in previous for loop) and print
    # diagonal starting at it.
    # arr[R-1][0], arr[R-1][1]....arr[R-1][c-1]
    # are all starting points
 
    # Note : we start from k = 1 to C-1;
    for k in range(1, C):
        print(arr[R-1][k], end="  ")
 
        # set row index for next point in diagonal
        i = R - 2
 
        # set column index for next point in diagonal
        j = k + 1
 
        # Print Diagonally upward
        while (isValid(i, j)):
            print(arr[i][j], end="  ")
            i -= 1
            j += 1  # move in upright direction
 
        print()
 
 
# Driver Code
arr = [[1, 2, 3, 4],
       [5, 6, 7, 8],
       [9, 10, 11, 12],
       [13, 14, 15, 16],
       [17, 18, 19, 20]]
 
# Function call
diagonalOrder(arr)
 
# This code is contributed by Nikita Tiwari.

C#

// C# Code for Zigzag (or diagonal)
// traversal of Matrix
using System;
 
class GFG {
    public static int R, C;
 
    private static void diagonalOrder(int[, ] arr)
    {
 
        /* through this for loop we
        choose each element of first
        column as starting point and
        print diagonal starting at it.
        arr[0,0], arr[1,0]....arr[R-1,0]
        are all starting points */
        for (int k = 0; k < R; k++)
        {
            Console.Write(arr[k, 0] + " ");
 
            // set row index for next
            // point in diagonal
            int i = k - 1;
           
            // set column index for
            // next point in diagonal
            int j = 1;
 
            /* Print Diagonally upward */
            while (isValid(i, j))
            {
                Console.Write(arr[i, j] + " ");
 
                i--;
               
                // move in upright direction
                j++;
            }
 
            Console.Write("\n");
        }
 
        /*  through this for loop we
            choose each element of last
            row as starting point (except
            the [0][c-1] it has already
            been processed in previous for
            loop) and print diagonal starting
            at it. arr[R-1,0], arr[R-1,1]....
            arr[R-1,c-1] are all starting points */
 
        // Note : we start from k = 1 to C-1;
        for (int k = 1; k < C; k++)
        {
            Console.Write(arr[R - 1, k] + " ");
 
            // set row index for next
            // point in diagonal
            int i = R - 2;
           
            // set column index for
            // next point in diagonal
            int j = k + 1;
 
            /* Print Diagonally upward */
            while (isValid(i, j))
            {
                Console.Write(arr[i, j] + " ");
 
                i--;
                j++; // move in upright direction
            }
 
            Console.Write("\n");
        }
    }
 
    public static bool isValid(int i, int j)
    {
        if (i < 0 || i >= R || j >= C || j < 0)
            return false;
        return true;
    }
 
    // Driver code
    public static void Main()
    {
        int[, ] arr = { { 1, 2, 3, 4 },
                        { 5, 6, 7, 8 },
                        { 9, 10, 11, 12 },
                        { 13, 14, 15, 16 },
                        { 17, 18, 19, 20 } };
 
        R = arr.GetLength(0);
        C = arr.GetLength(1);
 
        // Function call
        diagonalOrder(arr);
    }
}
 
// This code is contributed
// by ChitraNayal

PHP

<?php
// PHP code for Zigzag (or diagonal)
// traversal of Matrix
define("R", 5);
define("C", 4);
 
function isValid($i, $j)
{
    if ($i < 0 || $i >= R ||
        $j >= C || $j < 0) return false;
    return true;
}
 
function diagonalOrder(&$arr)
{
    /* through this for loop we choose
    each element of first column as
    starting point and print diagonal 
    starting at it.
    arr[0][0], arr[1][0]....arr[R-1][0]
    are all starting points */
    for ($k = 0; $k < R; $k++)
    {
        echo $arr[$k][0] . " ";
        $i = $k - 1; // set row index for next
                     // point in diagonal
        $j = 1; // set column index for next
                // point in diagonal
 
        /* Print Diagonally upward */
        while (isValid($i,$j))
        {
            echo $arr[$i][$j] . " ";
            $i--;
            $j++; // move in upright direction
        }
        echo "\n";
    }
 
    /* through this for loop we choose each
    element of last row as starting point
    (except the [0][c-1] it has already been
    processed in previous for loop) and print
    diagonal starting at it. arr[R-1][0],
    arr[R-1][1]....arr[R-1][c-1] are all
    starting points */
 
    //Note : we start from k = 1 to C-1;
    for ($k = 1; $k < C; $k++)
    {
        echo $arr[R - 1][$k] . " ";
        $i = R - 2; // set row index for next
                    // point in diagonal
        $j = $k + 1; // set column index for next
                     // point in diagonal
 
        /* Print Diagonally upward */
        while (isValid($i, $j))
        {
            echo $arr[$i][$j] . " ";
            $i--;
            $j++; // move in upright direction
        }
        echo "\n";
    }
}
 
// Driver Code
$arr = array(array(1, 2, 3, 4),
             array(5, 6, 7, 8),
             array(9, 10, 11, 12),
             array(13, 14, 15, 16),
             array(17, 18, 19, 20));
 
// Function call
diagonalOrder($arr);
 
// This code is contributed
// by rathbhupendra
?>

Javascript

<script>
// JAVA Code for Zigzag (or diagonal)
// traversal of Matrix
 
var R, C;
 
    function diagonalOrder( arr)
    {
 
        /* through this for loop we choose each
        element of first column as starting point
        and print diagonal starting at it. arr[0][0],
        arr[1][0]....arr[R-1][0] are all starting points */
        for (var k = 0; k < R; k++) {
            document.write(arr[k][0] + " ");
 
            // set row index for next
            // point in diagonal
            var i = k - 1;
           
            //  set column index for
            // next point in diagonal
            var j = 1;
 
            /* Print Diagonally upward */
            while (isValid(i, j))
            {
                document.write(arr[i][j] + " ");
 
                i--;
                
                // move in upright direction
                j++;
            }
 
            document.writeln("<br>");
        }
 
        /* through this for loop we choose each element
           of last row as starting point (except the
           [0][c-1] it has already been processed in
           previous for loop) and print diagonal
           starting at it. arr[R-1][0], arr[R-1][1]....
           arr[R-1][c-1] are all starting points */
 
        // Note : we start from k = 1 to C-1;
        for (var k = 1; k < C; k++) {
            document.write(arr[R - 1][k] + " ");
 
            // set row index for next
            // point in diagonal
            var i = R - 2;
           
            // set column index for
            // next point in diagonal
            var j = k + 1;
 
            /* Print Diagonally upward */
            while (isValid(i, j))
            {
                document.write(arr[i][j] + " ");
 
                // move in upright direction
                i--;
                j++;
            }
 
            document.writeln("<br>");
        }
    }
 
    function isValid( i,  j)
    {
        if (i < 0 || i >= R
            || j >= C || j < 0)
            return false;
        return true;
    }
 
    // Driver code
            var arr = [
            [ 1, 2, 3, 4 ],    
            [ 5, 6, 7, 8 ],
            [ 9, 10, 11, 12 ], 
            [ 13, 14, 15, 16 ],
            [ 17, 18, 19, 20 ],
        ];
 
        R = arr.length;
        C = arr[0].length;
 
        // Function call
        diagonalOrder(arr);
 
// This code is contributed by shivanisinghss2110
</script>
Producción

1 
5 2 
9 6 3 
13 10 7 4 
17 14 11 8 
18 15 12 
19 16 
20 

Complejidad temporal: O(fila x columna) 
Espacio auxiliar: O(1)

Gracias a Gaurav Ahirwar por sugerir este método. 

Este artículo fue compilado por Ashish Anand y revisado por el equipo de GeeksforGeeks. Escriba comentarios si encuentra algo incorrecto o si desea compartir más información sobre el tema tratado anteriormente.

Otro enfoque:

Es una observación aguda que la suma de [i+j], que son los índices de la array, permanece igual en toda la diagonal. Así que explotaremos esta propiedad de la array para que nuestro código sea corto y simple.

A continuación se muestra la implementación de la idea anterior:

C++

#include <bits/stdc++.h>
#define R 5
#define C 4
using namespace std;
 
void diagonalOrder(int arr[][C],
                   int n, int m)
{
    // we will use a 2D vector to
    // store the diagonals of our array
    // the 2D vector will have (n+m-1)
    // rows that is equal to the number of
    // diagonals
    vector<vector<int> > ans(n + m - 1);
 
    for (int i = 0; i < m; i++)
    {
        for (int j = 0; j < n; j++)
        {
            ans[i + j].push_back(arr[j][i]);
        }
    }
 
    for (int i = 0; i < ans.size(); i++)
    {
        for (int j = 0; j < ans[i].size(); j++)
            cout << ans[i][j] << " ";
 
        cout << endl;
    }
}
 
// Driver Code
int main()
{
    // we have a matrix of n rows
    // and m columns
    int n = 5, m = 4;
    int arr[][C] = {
        { 1, 2, 3, 4 },
        { 5, 6, 7, 8 },
        { 9, 10, 11, 12 },
        { 13, 14, 15, 16 },
        { 17, 18, 19, 20 },
    };
    
    // Function call
    diagonalOrder(arr, n, m);
    return 0;
}

Java

import java.util.*;
import java.io.*;
 
class GFG
{
  public static int R = 5, C = 4;
  public static void diagonalOrder(int[][] arr, int n, int m)
  {
 
    // we will use a 2D vector to
    // store the diagonals of our array
    // the 2D vector will have (n+m-1)
    // rows that is equal to the number of
    // diagonals
    ArrayList<ArrayList<Integer>> ans = new ArrayList<ArrayList<Integer>>(n+m-1);
    for(int i = 0; i < n + m - 1; i++)
    {
      ans.add(new ArrayList<Integer>());
    }
 
    for (int i = 0; i < n; i++)
    {
      for (int j = 0; j < m; j++)
      {
        (ans.get(i+j)).add(arr[i][j]);
      }
    }
 
    for (int i = 0; i < ans.size(); i++)
    {
      for (int j = ans.get(i).size() - 1; j >= 0; j--)
      {    System.out.print(ans.get(i).get(j)+ " ");
      }  
      System.out.println();
    }
  }
 
  // Driver code
  public static void main (String[] args) {
    int n = 5, m = 4;
    int[][] arr={
      { 1, 2, 3, 4 },
      { 5, 6, 7, 8 },
      { 9, 10, 11, 12 },
      { 13, 14, 15, 16 },
      { 17, 18, 19, 20 },
    };
 
    // Function call
    diagonalOrder(arr, n, m);
  }
}
 
// This code is contributed by Manu Pathria

Python3

R = 5
C = 5
def diagonalOrder(arr, n, m):
     
    # we will use a 2D vector to
    # store the diagonals of our array
    # the 2D vector will have (n+m-1)
    # rows that is equal to the number of
    # diagonals
    ans = [[] for i in range(n + m - 1)]
     
    for i in range(m):
        for j in range(n):
            ans[i + j].append(arr[j][i])
     
    for i in range(len(ans)):
        for j in range(len(ans[i])):
            print(ans[i][j], end = " ")
        print()
 
# Driver Code
# we have a matrix of n rows
# and m columns
n = 5
m = 4
 
# Function call
arr = [[1, 2, 3, 4],[ 5, 6, 7, 8],[9, 10, 11, 12 ],[13, 14, 15, 16 ],[ 17, 18, 19, 20]]
diagonalOrder(arr, n, m)
 
# This code is contributed by rag2127

C#

using System;
using System.Collections.Generic;
 
public class GFG
{
 
  public static int R = 5, C = 4;
  public static void diagonalOrder(int[,] arr, int n, int m)
  {
 
    // we will use a 2D vector to
    // store the diagonals of our array
    // the 2D vector will have (n+m-1)
    // rows that is equal to the number of
    // diagonals
    List<List<int>> ans = new List<List<int>>(n+m-1);
    for(int i = 0; i < n + m - 1; i++)
    {
      ans.Add(new List<int>());
    }
 
    for (int i = 0; i < n; i++)
    {
      for (int j = 0; j < m; j++)
      {
        (ans[i + j]).Add(arr[i, j]);
      }
    }
 
    for (int i = 0; i < ans.Count; i++)
    {
      for (int j = ans[i].Count - 1; j >= 0; j--)
      {   
        Console.Write(ans[i][j] + " ");
      }  
      Console.WriteLine();
    }
 
  }
  // Driver code
  static public void Main ()
  {
    int n = 5, m = 4;
    int[,] arr={
      { 1, 2, 3, 4 },
      { 5, 6, 7, 8 },
      { 9, 10, 11, 12 },
      { 13, 14, 15, 16 },
      { 17, 18, 19, 20 },
    };
 
    // Function call
    diagonalOrder(arr, n, m);
  }
}
 
// This code is contributed by avanitrachhadiya2155

Javascript

<script>
 
var R = 5;
var C = 4;
 
function diagonalOrder(arr, n, m)
{
    // we will use a 2D vector to
    // store the diagonals of our array
    // the 2D vector will have (n+m-1)
    // rows that is equal to the number of
    // diagonals
    var ans = Array.from(Array(n+m-1), ()=>Array());
 
    for (var i = 0; i < n; i++)
    {
        for (var j = 0; j < m; j++)
        {
            ans[i + j].push(arr[i][j]);
        }
    }
 
    for (var i = 0; i < ans.length; i++)
    {
      for (var j = ans[i].length - 1; j >= 0; j--)
      {   
        document.write(ans[i][j] + " ");
      }  
      document.write("<br>");
    }
}
 
// Driver Code
// we have a matrix of n rows
// and m columns
var n = 5, m = 4;
var arr = [
    [ 1, 2, 3, 4 ],
    [ 5, 6, 7, 8 ],
    [ 9, 10, 11, 12 ],
    [ 13, 14, 15, 16 ],
    [ 17, 18, 19, 20 ],
];
 
// Function call
diagonalOrder(arr, n, m);
 
// This code is contributed by rrrtnx.
</script>
Producción

1 
5 2 
9 6 3 
13 10 7 4 
17 14 11 8 
18 15 12 
19 16 
20 

 
Complejidad de Tiempo: O(fila x columna) 
Espacio Auxiliar: O(fila + columna)

Publicación traducida automáticamente

Artículo escrito por GeeksforGeeks-1 y traducido por Barcelona Geeks. The original can be accessed here. Licence: CCBY-SA

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