蓝桥杯2022统计子矩阵

P2036 - [蓝桥杯2022初赛] 统计子矩阵 - New Online Judgehttp://oj.ecustacm.cn/problem.php?id=2036暴力能过80%的数据。。。

#include 
typedef long long ll;
using namespace std;
ll a[512][512] = { 0 };
ll sum[512][512] = { 0 }; // sum[i][j]表示从a[1][1]到a[i][j]的和
int main() {
    // system("chcp 65001");
    ios::sync_with_stdio(false);
    cin.tie(0);
    // freopen("C:/Users/zhaochen/Desktop/input.txt", "r", stdin);
    int n, m, k;
    cin >> n >> m >> k;
    ll ans = 0;
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            cin >> a[i][j];
        }
    }
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) {
            sum[i][j] = sum[i - 1][j] + sum[i][j - 1] - sum[i - 1][j - 1] + a[i][j];
        }
    }
    for (int i = 1; i <= n; i++) {
        for (int j = 1; j <= m; j++) { // 左上角
            for (int p = i; p <= n; p++) {
                for (int q = j; q <= m; q++) { // 右下角
                    ll t = sum[p][q] - sum[p][j - 1] - sum[i - 1][q] + sum[i - 1][j - 1];
                    if (t <= k) {
                        ans++;
                    } else {
                        break;
                    }
                }
            }
        }
    }
    cout << ans;
    return 0;
}