recursion_adv.cpp

#include<iostream>
#include<string>
using namespace std;

// recursion op in the chat

void permutation(string s, string answer) {
    if(s.length()==0) {
        cout<<answer<<endl;
        return;
    }
    for(int i=0;i<s.length();i++) {
        string rem=s.substr(0, i)+s.substr(i+1);
        permutation(rem, answer+s[i]);
    }
}
int total_path(int pos) {
    if(pos<0)return 0;
    if(pos==0|| pos==1)return 1;
    return (total_path(pos-1))+(total_path(pos-2))+(total_path(pos-3))+(total_path(pos-4))+(total_path(pos-5))+(total_path(pos-6));
}
int count_path(int s, int e) {

    if(s==e) {
        return 1;
    }
    if(s>e) {
        return 0;
    }
    int count=0;
    for(int i=1;i<=6;i++) {
        count+=count_path(s+i, e);
    }
    return count;
}
int maze_path(int i, int j) {
    if(i<0 || j<0)return 0;
    if(i==0 || j==0)return 1;
    return maze_path(i-1, j)+ maze_path(i, j-1);
}

int main() {

    string s="";
    permutation("har", s);


    // cout<<total_path(25)<<endl;
    // cout<<count_path(0,25)<<endl;

    // cout<<maze_path(5,5)<<endl;
    return 0;
}