Dada una gráfica de N Nodes, E aristas, un Node X y una distancia K . La tarea es imprimir todos los Nodes dentro de la distancia K de X.
Aporte:
Salida: 4 5 2 7 3
Los Nodes vecinos dentro de la distancia 2 del Node 4 son: 4 5 2 7 3
Aproximación:
Para imprimir todos los Nodes que se encuentren a una distancia K o inferior a K . Podemos hacerlo aplicando la variación dfs , que toma el Node K desde donde tenemos que imprimir la distancia hasta la distancia K.
dfs(K, node, -1, tree)
Aquí -1 indica el padre del Node.
Esta función recursiva básicamente imprime el Node y luego llama al dfs(K-1, vecino del Node, Node, árbol) .
La condición base es K>0.
A continuación se muestra la implementación del enfoque anterior:
C++
// C++ program to print
// the nearest K neighbour
// nodes (including itself)
#include <bits/stdc++.h>
using namespace std;
// Structure of an edge
struct arr {
int from, to;
};
// Recursive function to print
// the neighbor nodes of a node
// until K distance
void dfs(int k, int node,
int parent,
const vector<vector<int> >& tree)
{
// Base condition
if (k < 0)
return;
// Print the node
cout << node << ' ';
// Traverse the connected
// nodes/adjacency list
for (int i : tree[node]) {
if (i != parent) {
// node i becomes the parent
// of its child node
dfs(k - 1, i, node, tree);
}
}
}
// Function to print nodes under
// distance k
void print_under_dis_K(struct arr graph[],
int node, int k,
int v, int e)
{
// To make graph with
// the given edges
vector<vector<int> > tree(v + 1,
vector<int>());
for (int i = 0; i < e; i++) {
int from = graph[i].from;
int to = graph[i].to;
tree[from].push_back(to);
tree[to].push_back(from);
}
dfs(k, node, -1, tree);
}
// Driver Code
int main()
{
// Number of vertex and edges
int v = 7, e = 6;
// Given edges
struct arr graph[v + 1] = {
{ 2, 1 },
{ 2, 5 },
{ 5, 4 },
{ 5, 7 },
{ 4, 3 },
{ 7, 6 }
};
// k is the required distance
// upto which are neighbor
// nodes should get printed
int node = 4, k = 2;
// function calling
print_under_dis_K(graph, node, k, v, e);
return 0;
}
Java
// Java program to print
// the nearest K neighbour
// nodes (including itself)
import java.util.*;
@SuppressWarnings("unchecked")
class GFG{
// Structure of an edge
public static class arr
{
public int from, to;
public arr(int from, int to)
{
this.from = from;
this.to = to;
}
};
// Recursive function to print
// the neighbor nodes of a node
// until K distance
static void dfs(int k, int node,
int parent, ArrayList []tree)
{
// Base condition
if (k < 0)
return;
// Print the node
System.out.print(node + " ");
ArrayList tmp = (ArrayList)tree[node];
// Traverse the connected
// nodes/adjacency list
for(int i : (ArrayList<Integer>)tmp)
{
if (i != parent)
{
// Node i becomes the parent
// of its child node
dfs(k - 1, i, node, tree);
}
}
}
// Function to print nodes under
// distance k
static void print_under_dis_K(arr []graph,
int node, int k,
int v, int e)
{
// To make graph with
// the given edges
ArrayList []tree = new ArrayList[v + 1];
for(int i = 0; i < v + 1; i++)
{
tree[i] = new ArrayList();
}
for(int i = 0; i < e; i++)
{
int from = graph[i].from;
int to = graph[i].to;
tree[from].add(to);
tree[to].add(from);
}
dfs(k, node, -1, tree);
}
// Driver Code
public static void main(String[] args)
{
// Number of vertex and edges
int v = 7, e = 6;
// Given edges
arr []graph = { new arr(2, 1),
new arr(2, 5),
new arr(5, 4),
new arr(5, 7),
new arr(4, 3),
new arr(7, 6) };
// k is the required distance
// upto which are neighbor
// nodes should get printed
int node = 4, k = 2;
// Function calling
print_under_dis_K(graph, node, k, v, e);
}
}
// This code is contributed by pratham76
Python3
# Python3 program to print # the nearest K neighbour # nodes (including itself) tree = [[] for i in range(100)] # Recursive function to print # the neighbor nodes of a node # until K distance def dfs(k, node, parent): # Base condition if (k < 0): return # Print the node print(node, end = " ") # Traverse the connected # nodes/adjacency list for i in tree[node]: if (i != parent): # node i becomes the parent # of its child node dfs(k - 1, i, node) # Function to print nodes under # distance k def print_under_dis_K(graph, node, k, v, e): for i in range(e): fro = graph[i][0] to = graph[i][1] tree[fro].append(to) tree[to].append(fro) dfs(k, node, -1) # Driver Code # Number of vertex and edges v = 7 e = 6 # Given edges graph = [[ 2, 1 ], [ 2, 5 ], [ 5, 4 ], [ 5, 7 ], [ 4, 3 ], [ 7, 6 ]] # k is the required distance # upto which are neighbor # nodes should get pred node = 4 k = 2 # function calling print_under_dis_K(graph, node, k, v, e) # This code is contributed by Mohit Kumar
C#
// C# program to print
// the nearest K neighbour
// nodes (including itself)
using System;
using System.Collections;
class GFG
{
// Structure of an edge
public class arr
{
public int from, to;
public arr(int from, int to)
{
this.from = from;
this.to = to;
}
};
// Recursive function to print
// the neighbor nodes of a node
// until K distance
static void dfs(int k, int node,
int parent, ArrayList []tree)
{
// Base condition
if (k < 0)
return;
// Print the node
Console.Write(node+" ");
ArrayList tmp = (ArrayList)tree[node];
// Traverse the connected
// nodes/adjacency list
foreach (int i in tmp)
{
if (i != parent)
{
// node i becomes the parent
// of its child node
dfs(k - 1, i, node, tree);
}
}
}
// Function to print nodes under
// distance k
static void print_under_dis_K(arr []graph,
int node, int k,
int v, int e)
{
// To make graph with
// the given edges
ArrayList []tree = new ArrayList[v + 1];
for(int i = 0; i < v + 1; i++)
{
tree[i] = new ArrayList();
}
for (int i = 0; i < e; i++)
{
int from = graph[i].from;
int to = graph[i].to;
tree[from].Add(to);
tree[to].Add(from);
}
dfs(k, node, -1, tree);
}
// Driver Code
public static void Main(string[] args)
{
// Number of vertex and edges
int v = 7, e = 6;
// Given edges
arr []graph = {
new arr( 2, 1 ),
new arr( 2, 5 ),
new arr( 5, 4 ),
new arr( 5, 7 ),
new arr( 4, 3 ),
new arr( 7, 6 )
};
// k is the required distance
// upto which are neighbor
// nodes should get printed
int node = 4, k = 2;
// function calling
print_under_dis_K(graph, node, k, v, e);
}
}
// This code is contributed by rutvik_56
Javascript
<script>
// JavaScript program to print
// the nearest K neighbour
// nodes (including itself)
// Structure of an edge
class arr
{
constructor(from,to)
{
this.from = from;
this.to = to;
}
}
// Recursive function to print
// the neighbor nodes of a node
// until K distance
function dfs(k,node,parent,tree)
{
// Base condition
if (k < 0)
return;
// Print the node
document.write(node + " ");
let tmp = tree[node];
// Traverse the connected
// nodes/adjacency list
for(let i=0;i<tmp.length;i++)
{
if (tmp[i] != parent)
{
// Node i becomes the parent
// of its child node
dfs(k - 1, tmp[i], node, tree);
}
}
}
// Function to print nodes under
// distance k
function print_under_dis_K(graph,node,k,v,e)
{
// To make graph with
// the given edges
let tree = new Array(v + 1);
for(let i = 0; i < v + 1; i++)
{
tree[i] = [];
}
for(let i = 0; i < e; i++)
{
let from = graph[i].from;
let to = graph[i].to;
tree[from].push(to);
tree[to].push(from);
}
dfs(k, node, -1, tree);
}
// Driver Code
// Number of vertex and edges
let v = 7, e = 6;
// Given edges
let graph = [ new arr(2, 1),
new arr(2, 5),
new arr(5, 4),
new arr(5, 7),
new arr(4, 3),
new arr(7, 6) ];
// k is the required distance
// upto which are neighbor
// nodes should get printed
let node = 4, k = 2;
// Function calling
print_under_dis_K(graph, node, k, v, e);
// This code is contributed by unknown2108
</script>
Producción:
4 5 2 7 3