最少操作次數

#include<bits/stdc++.h>
using namespace std;

int main() {

    ios::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);

    string s;
    cin >> s >> s;

    int n = s.size();

    vector<int> cnt(2, 0);
    for (int i = 0; i < n; ++ i) {
        cnt[s[i] - '0'] += 1;
    }

    if (cnt[0] == 0 or cnt[1] == 0) {
        cout << "0\n";
    } else if (cnt[0] != cnt[1]) {
        cout << "1\n";
    } else if (s == "01" or s == "10") {
        cout << "-1\n";
    } else {
        cout << "2\n";
    }

    return 0;
}