405C - Unusual Product - CodeForces Solution

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define sz(s) (int)s.size()
#define all(v) (v).begin(),(v).end()
#define fx(x) fixed<<setprecision(x);
#define SKADOOSH ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
const double PI = acos(-1.0);


void file()
{
#ifndef ONLINE_JUDGE
    //freopen("in.txt", "r", stdin);
    //freopen("out.txt", "w", stdout);
#else
    //freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
#endif
}

int main()
{
    SKADOOSH;
    int n;
    cin>>n;
    vector<int>v(n);
    int sum=0;
    for(int i=0; i<n; i++)
    {
        for(int j=0; j<n; j++)
        {
            bool che;
            cin>>che;
            if(i==j)
            {
                v[i]=che;
                sum+=v[i];
            }
        }
    }
    int m;
    cin>>m;
    while(m--)
    {
        int oper;
        cin>>oper;
        if(oper==3)
        {
            cout<<(sum&1);
        }
        else
        {
            int val;
            cin>>val;
            if(v[val-1])
                sum--;
            else
                sum++;
            v[val]=!v[val];
        }
    }
}