样例和下载数据都过了，为什么全WA

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

signed main() {
    string s;
    getline (cin,s);
    int n=s.size();
    for (int i=1; i<n; ++i) {
        string a;
        getline (cin,a);
        s+=a;
    }
    cout << n << " ";
    int i=0;
    int sum=0;
    if (s[0]=='1') {
        cout << 0 << " ";
        sum++;
        i++;
    } else {
        sum++;
        i++;
    }
    while (i<=n*n) {
        if (s[i]==s[i-1]) {
            sum++;
            i++;
        } else {
            cout << sum << " ";
            sum=1;
            i++;
        }
    }
    return 0;
}

请各位大佬帮个忙