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29 lines
791 B
29 lines
791 B
#include <bits/stdc++.h>
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using namespace std;
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const int N = 330;
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int n;
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int a[N][N], s[N][N], dp[N];
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int res = INT_MIN;
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int main() {
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cin >> n;
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// 前缀和(竖直方向)
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for (int i = 1; i <= n; i++)
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for (int j = 1; j <= n; j++) {
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cin >> a[i][j];
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s[i][j] = s[i - 1][j] + a[i][j]; // 一维前缀和，这可不是二维前缀和
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}
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// 降维变成一维dp
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for (int i = 0; i <= n - 1; i++) // 枚举左上角
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for (int j = i + 1; j <= n; j++) // 枚举右下角
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for (int k = 1; k <= n; k++) {
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dp[k] = max(s[j][k] - s[i][k], dp[k - 1] + s[j][k] - s[i][k]);
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res = max(res, dp[k]);
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}
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// 输出
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cout << res << endl;
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return 0;
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}
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