# HackerEarth Binary Swap problem solution

In this HackerEarth Binary Swap problem solution You are given two binary strings A and B of equal length. You have a type of opertion in which you can swap any two elements of string B. Your task is to find the minimum number of operations required to convert string B into string A. If it is not possible, print -1.

## HackerEarth Binary Swap problem solution.

`#include <bits/stdc++.h>#define ll long long#define ull unsigned long long#define pb push_back#define mp make_pair#define fi first#define se second#define be begin()#define en end()#define le length()#define sz size()#define all(x) (x).begin(),(x).end()#define alli(a, n, k) (a+k),(a+n+k)#define REP(i, a, b, k) for(__typeof(a) i = a;i < b;i += k)#define REPI(i, a, b, k) for(__typeof(a) i = a;i > b;i -= k)#define REPITER(it, a) for(__typeof(a.begin()) it = a.begin();it != a.end(); ++it)#define y0 sdkfaslhagaklsldk#define y1 aasdfasdfasdf#define yn askfhwqriuperikldjk#define j1 assdgsdgasghsf#define tm sdfjahlfasfh#define lr asgasgash#define norm asdfasdgasdgsd#define have adsgagshdshfhds#define eps 1e-6#define pi 3.141592653589793using namespace std;template<class T> inline T gcd(T a, T b) { while(b) b ^= a ^= b ^= a %= b; return a; }template<class T> inline T mod(T x) { if(x < 0) return -x; else return x; }typedef vector<int> VII;typedef vector<ll> VLL;typedef pair<int, int> PII;typedef pair<ll, ll> PLL;typedef pair<int, PII > PPII;typedef vector< PII > VPII;typedef vector< PPII > VPPI;const int MOD = 1e9 + 7;const int INF = 1e9;// Template Endint main(int argc, char* argv[]) {    if(argc == 2 or argc == 3) freopen(argv[1], "r", stdin);    if(argc == 3) freopen(argv[2], "w", stdout);    ios::sync_with_stdio(false);    string a, b;    int o = 0, e = 0;    cin >> a >> b;    REP(i, 0, a.le, 1) {        if (a[i] != b[i]) {            if (b[i] == '1') o++;            else e++;        }    }    if (o == e) cout << o << endl;    else cout << -1 << endl;    return 0;}`

### Second solution

`#include<bits/stdc++.h>using namespace std;int main(){  string a,b;  int o=0,z=0;  cin>>a>>b;  for(int i=0;i<a.size();i++)  {    if(a[i]!=b[i])    {      if(a[i]=='1')o++;      else z++;    }  }  if(o!=z)cout<<"-1\n";  else cout<<o<<"\n";  return 0;}`