#include "fish.h"
#include<bits/stdc++.h>
using namespace std;
#define int long long int
int pref[3005][3005];
int query(int j, int i1, int i2) {
if (i1 > i2) {
return 0;
}
return pref[i2][j]-pref[i1-1][j];
}
int max_weights(int32_t N, int32_t M, vector<int32_t> X, vector<int32_t> Y, vector<int32_t> W) {
int n = N, m = M;
vector<vector<int>> c(n+1, vector<int>(n+1, 0));
vector<vector<int>> dp(n+1, vector<int>(2, 0)), tdp(n+1, vector<int>(2, 0)); // 0 is increasing, 1 is decreasing, increasing can go to decreasing, decreasing cant go to increasing if next to eachother
for (int i = 0; i < m; i++) {
c[Y[i]+1][X[i]] = W[i];
pref[Y[i]+1][X[i]] = W[i];
}
for (int j = 0; j < n; j++) {
for (int i = 1; i <= n; i++) {
pref[i][j] += pref[i-1][j];
}
}
for (int j = 1; j <= n; j++) {
int v = 0;
for (int i = 0; i <= n; i++) {
v = max(v, dp[i][0]-pref[i][j-1]);
tdp[i][0] = max(v+pref[i][j-1], dp[0][1]);
}
v = 0;
for (int i = n; i >= 0; i--) {
v= max(v, max(dp[i][0], dp[i][1])+pref[i][j]);
tdp[i][1] = v-pref[i][j];
}
swap(dp, tdp);
}
int ans = max(dp[0][0], dp[0][1]);
return ans;
}
