七夕祭

 

 

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 100010;
int row[N], col[N], s[N], c[N];
//s是前缀和数组
ll work(int n, int a[]) {
    //先求前缀和
    for (int i = 1; i <= n; i++) {
        s[i] = s[i - 1] + a[i];
    }
    if (s[n] % n) {
        return -1;
    }
    int avg = s[n] / n;
    //求c数组
    c[1] = 0;
    for (int i = 2; i <= n; i++) {
        c[i] = s[i - 1] - (i - 1) * avg;
    }
    sort(c + 1, c + 1 + n);
    ll res = 0;
    for (int i = 1; i <= n; i++) {
        res += abs(c[i] - c[(n + 1) / 2]);
    }
    return res;
}
int main() {
    int n, m, cnt;
    cin >> n >> m >> cnt;
    for (int i = 0; i < cnt; i++) {
        int x, y;
        cin >> x >> y;
        row[x]++;
        col[y]++;
    }
    ll r = work(n, row);
    ll c = work(m, col);
    //返回-1说明无解
    if (r != -1 && c != -1) {
        cout << "both " << r + c << endl;
    } else if (r != -1) {
        cout << "row " << r << endl;
    } else if (c != -1) {
        cout << "column " << c << endl;
    } else {
        cout << "impossible" << endl;
    }
    return 0;
}