Inversions

input/code.cpp:5:7: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main () {
       ^
input/code.cpp: In function 'int main()':
input/code.cpp:11:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < s.size(); ++i) {
                     ~~^~~~~~~~~~

#include <bits/stdc++.h>

using namespace std;

main () {
    string s;
    cin >> s;
    
    int s1 = 0, s2 = 0;
    
    for (int i = 0; i < s.size(); ++i) {
        
        if (i % 2 == 0) {
            if (s[i] == '0')
                s2 ++;
            if (s[i] == '1')
                s1 ++;
        } else {
            if (s[i] == '0')
                s1 ++;
            if (s[i] == '1')
                s2 ++;
        }
    }
    
    cout << min(s1, s2) << endl;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED