Inversions

input/code.cpp: In function 'int main()':
input/code.cpp:8:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0;i<s.size();++i){
                  ~^~~~~~~~~

#include <iostream>
using namespace std;
string s;
int main(){
    ios_base::sync_with_stdio(0);cin.tie(0);
    cin >> s;
    int a=0;int b=0;
    for (int i=0;i<s.size();++i){
        a+=(s[i]=='1')==(i&1);
        b+=(s[i]=='1')!=(i&1);
    }
    cout << min(a, b) << "\n";
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED