Recuento de permutaciones distintas de cada longitud posible de string dada

Dada una string S, la tarea es contar las distintas permutaciones de cada longitud posible de la string dada.

Nota: No se permite la repetición de caracteres en la string.

Entrada: S = “abc”
Salida: 15
Explicación:
Las permutaciones posibles de cada longitud son:
{“a”, “b”, “c”, “ab”, “bc”, “ac”, “ba”, “ca ”, “cb”, “abc”, “acb”, “bac”, “bca”, “taxi”, “cba”}

Entrada: S = “xz”
Salida: 4

Enfoque: La idea es encontrar el número de combinaciones de todas las longitudes posibles de la string y su suma es el número total de permutaciones distintas posibles de diferentes longitudes. Por lo tanto, para una string de longitud N, el número total de permutaciones distintas de diferente longitud es:

Combinaciones totales posibles: ⁿ P ₁ + ⁿ P ₂ + ⁿ P ₃ + ⁿ P ₄ + …… + ⁿ P _n

A continuación se muestra la implementación del enfoque anterior:

// C++ implementation of the
// above approach
 
#include <bits/stdc++.h>
#include <iostream>
using namespace std;
 
// Function to find the factorial
// of a number
int fact(int a)
{
    int i, f = 1;
 
    // Loop to find the factorial
    // of the given number
    for (i = 2; i <= a; i++)
        f = f * i;
    return f;
}
 
// Function to find the number
// of permutations possible
// for a given string
int permute(int n, int r)
{
    int ans = 0;
    ans = (fact(n) / fact(n - r));
    return ans;
}
 
// Function to find the total
// number of combinations possible
int findPermutations(int n)
{
    int sum = 0, P;
    for (int r = 1; r <= n; r++) {
        P = permute(n, r);
        sum = sum + P;
    }
    return sum;
}
 
// Driver Code
int main()
{
    string str = "xz";
    int result, n;
    n = str.length();
 
    cout << findPermutations(n);
    return 0;
}

// Java implementation of the
// above approach
class GFG{
 
// Function to find the factorial
// of a number
static int fact(int a)
{
    int i, f = 1;
 
    // Loop to find the factorial
    // of the given number
    for(i = 2; i <= a; i++)
        f = f * i;
     
    return f;
}
 
// Function to find the number
// of permutations possible
// for a given String
static int permute(int n, int r)
{
    int ans = 0;
    ans = (fact(n) / fact(n - r));
    return ans;
}
 
// Function to find the total
// number of combinations possible
static int findPermutations(int n)
{
    int sum = 0, P;
    for(int r = 1; r <= n; r++)
    {
        P = permute(n, r);
        sum = sum + P;
    }
    return sum;
}
 
// Driver Code
public static void main(String[] args)
{
    String str = "xz";
    int result, n;
    n = str.length();
 
    System.out.print(findPermutations(n));
}
}
 
// This code is contributed by Amit Katiyar

# Python3 program to implement
# the above approach
 
# Function to find the factorial
# of a number
def fact(a):
 
    f = 1
 
    # Loop to find the factorial
    # of the given number
    for i in range(2, a + 1):
        f = f * i
 
    return f
 
# Function to find the number
# of permutations possible
# for a given string
def permute(n, r):
 
    ans = 0
    ans = fact(n) // fact(n - r)
 
    return ans
 
# Function to find the total
# number of combinations possible
def findPermutations(n):
 
    sum = 0
    for r in range(1, n + 1):
        P = permute(n, r)
        sum = sum + P
 
    return sum
 
# Driver Code
str = "xz"
n = len(str)
 
# Function call
print(findPermutations(n))
 
# This code is contributed by Shivam Singh

// C# implementation of the
// above approach
using System;
 
class GFG{
 
// Function to find the factorial
// of a number
static int fact(int a)
{
    int i, f = 1;
 
    // Loop to find the factorial
    // of the given number
    for(i = 2; i <= a; i++)
        f = f * i;
     
    return f;
}
 
// Function to find the number
// of permutations possible
// for a given String
static int permute(int n, int r)
{
    int ans = 0;
    ans = (fact(n) / fact(n - r));
    return ans;
}
 
// Function to find the total
// number of combinations possible
static int findPermutations(int n)
{
    int sum = 0, P;
    for(int r = 1; r <= n; r++)
    {
        P = permute(n, r);
        sum = sum + P;
    }
    return sum;
}
 
// Driver Code
public static void Main(String[] args)
{
    String str = "xz";
    int n;
    n = str.Length;
 
    Console.Write(findPermutations(n));
}
}
 
// This code is contributed by amal kumar choubey

<script>
 
// Javascript implementation of the
// above approach
 
// Function to find the factorial
// of a number
function fact(a)
{
    var i, f = 1;
 
    // Loop to find the factorial
    // of the given number
    for (i = 2; i <= a; i++)
        f = f * i;
    return f;
}
 
// Function to find the number
// of permutations possible
// for a given string
function permute(n, r)
{
    var ans = 0;
    ans = (fact(n) / fact(n - r));
    return ans;
}
 
// Function to find the total
// number of combinations possible
function findPermutations(n)
{
    var sum = 0, P;
    for (var r = 1; r <= n; r++) {
        P = permute(n, r);
        sum = sum + P;
    }
    return sum;
}
 
// Driver Code
var str = "xz";
var result, n;
n = str.length;
document.write( findPermutations(n));
 
</script>

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