只过了#1,#5

#include <iostream>
#include <vector>
#include <algorithm>
using namespace std;
int main() {
    int N;
    cin >> N;
    vector<vector<int>> grid(N, vector<int>(N));
    int x, y, value;
    while (true) {
        cin >> x >> y >> value;
        if (x == 0 && y == 0 && value == 0)
        {
            break;
        }
        grid[x - 1][y - 1] = value;
    }
    vector<vector<int>> dp1(N, vector<int>(N)), dp2(N, vector<int>(N));
    dp1[0][0] = grid[0][0];
    for (int i = 1; i < N; ++i) {
        dp1[i][0] = dp1[i - 1][0] + grid[i][0];
    }
    for (int j = 1; j < N; ++j) {
        dp1[0][j] = dp1[0][j - 1] + grid[0][j];
    }
    for (int i = 1; i < N; ++i) {
        for (int j = 1; j < N; ++j) {
            dp1[i][j] = max(dp1[i - 1][j], dp1[i][j - 1]) + grid[i][j];
        }
    }

    dp2[N - 1][N - 1] = grid[N - 1][N - 1];
    for (int i = N - 2; i >= 0; --i)
        dp2[i][N - 1] = dp2[i + 1][N - 1] + grid[i][N - 1];
    for (int j = N - 2; j >= 0; --j)
        dp2[N - 1][j] = dp2[N - 1][j + 1] + grid[N - 1][j];
    for (int i = N - 2; i >= 0; --i) {
        for (int j = N - 2; j >= 0; --j) {
            dp2[i][j] = max(dp2[i + 1][j], dp2[i][j + 1]) + grid[i][j];
        }
    }

    int maxs = 0;
    for (int i = 0; i < N; ++i) {
        for (int j = 0; j < N; ++j) {
            maxs = max(maxs, dp1[i][j] + dp2[i][j]);
        }
    }
    cout << maxs << endl;
    return 0;
}