diff --git a/Luogu/P1719/P1719.cpp b/Luogu/P1719/P1719.cpp new file mode 100644 index 00000000..f31d619f --- /dev/null +++ b/Luogu/P1719/P1719.cpp @@ -0,0 +1,46 @@ +#include +#include + +using std::cin; +using std::cout; +const char endl = '\n'; + +const int N = 125; + +int n, a[N][N], s[N][N], + ans = std::numeric_limits::min(); + +int main() { + std::ios::sync_with_stdio(false); + cin.tie(nullptr); + + cin >> n; + + for (int i = 1; i <= n; i++) { + for (int j = 1; j <= n; j++) { + cin >> a[i][j]; + } + } + + // 二维前缀和 + for (int i = 1; i <= n; i++) { + for (int j = 1; j <= n; j++) { + s[i][j] = s[i - 1][j] + s[i][j - 1] - s[i - 1][j - 1] + a[i][j]; + } + } + + // 枚举矩形的左上角和右下角 + for (int x1 = 1; x1 <= n; x1++) { + for (int y1 = 1; y1 <= n; y1++) { + for (int x2 = x1; x2 <= n; x2++) { + for (int y2 = y1; y2 <= n; y2++) { + ans = std::max(ans, s[x2][y2] - s[x1 - 1][y2] - s[x2][y1 - 1] + s[x1 - 1][y1 - 1]); + } + } + } + } + + cout << ans << endl; + + return 0; +}