CPP

permutation in c++ with backtracking

// C++ program to print all
// permutations with duplicates allowed
#include <bits/stdc++.h>
using namespace std;
 
 
// Function to print permutations of string
// This function takes three parameters:
// 1. String
// 2. Starting index of the string
// 3. Ending index of the string.
void permute(string a, int l, int r)
{
    // Base case
    if (l == r)
        cout<<a<<endl;
    else
    {
        // Permutations made
        for (int i = l; i <= r; i++)
        {
 
            // Swapping done
            swap(a[l], a[i]);
 
            // Recursion called
            permute(a, l+1, r);
 
            //backtrack
            swap(a[l], a[i]);
        }
    }
}
 
// Driver Code
int main()
{
    string str = "ABC";
    int n = str.size();
    permute(str, 0, n-1);
    return 0;
}
 
// This is code is contributed by rathbhupendra