Codeforces Round #272 (Div. 2) 476B - Dreamoon and WiFi Solution

 

Problem Link: https://codeforces.com/problemset/problem/476/B

Solve in C++:  

///La ilaha illellahu muhammadur rasulullah

///******Bismillahir-Rahmanir-Rahim******///

///Abul Hasnat  Tonmoy

///Department of CSE,23rd batch

///Islamic University,Bangladesh

///**********ALLAH IS ALMIGHTY************///

#include<bits/stdc++.h>

using namespace std;

int main()

{

    ios::sync_with_stdio(false);

    cin.tie(0);

    string a,b;

    cin>>a>>b;

    int i,pa=0,pb=0,q=0,cn=0;

    for(i=0; i<a.size(); i++)

    {

        if(a[i]=='+')

            pa++;

         if(b[i]=='+')

            pb++;

         if(b[i]=='?')

            q++;

    }

    double v=1<<q;

    for(i=0; i<v; i++)

    {

        if(__builtin_popcount(i)+pb==pa)

            cn++;

    }

    cout<<fixed<<setprecision(9)<<(double)cn/v<<endl;

}