#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
typedef pair<int, pii> pipii;
typedef pair<pii, int> piipi;
typedef pair<pii, pii> piipii;
#define mp make_pair
#define fi first
#define se second
#define all(a) (a).begin(), (a).end()
#define sz(a) (int)(a).size()
#define eb emplace_back
ll dp[3005][3005][3]; // A(a), (A)a, (A)
int pos[3005][3005];
ll max_weight(int n, int m, vector<int> x, vector<int> y, vector<int> w) {
for(int i=0;i<x.size();i++) pos[x[i]+1][y[i]+1] = w[i];
memset(dp, -1, sizeof(dp));
ll ans = 0;
for(int i=1;i<=n;i++){
ll pref[3][3005];
ll suff[3005];
memset(suff, 0, sizeof(suff));
memset(pref, 0, sizeof(pref));
for(int j=1;j<=n;j++){
pref[0][j] = pref[0][j-1] + pos[i-1][j];
pref[1][j] = pref[1][j-1] + pos[i][j];
pref[2][j] = pref[2][j-1] + pos[i+1][j];
}
for(int j=n;j>=1;j--){
suff[j] = max(suff[j+1], dp[i-1][j][0]);
}
if(i == 1){
for(int j=0;j<=n;j++) dp[i][j][2] = 0;
}
else{
// 0
ll mx = -1e18;
for(int j=n;j>=0;j--){
if(dp[i-1][j][0] != -1) mx = max(mx, dp[i-1][j][0] + pref[1][j]);
dp[i][j][0] = max(dp[i][j][0], mx - pref[1][j]);
}
// 1
mx = 1e18;
for(int j=n;j>=0;j--){
dp[i][j][1] = max(dp[i][j][1], dp[i-1][j][0] + pref[1][j]);
dp[i][j][1] = max(dp[i][j][1], dp[i-1][j][2] + pref[1][j]);
}
// 2
ll mx0 = -1e18, mx1 = -1e18, mx2 = -1e18;
for(int j=0;j<=n;j++){
if(dp[i-1][j][0] != -1) mx0 = max(mx0, dp[i-1][j][0]);
if(dp[i-1][j][1] != -1) mx1 = max(mx1, dp[i-1][j][1] - pref[0][j]);
if(dp[i-1][j][2] != -1) mx2 = max(mx2, dp[i-1][j][2] - pref[0][j]);
dp[i][j][2] = max(dp[i][j][2], mx0);
dp[i][j][2] = max(dp[i][j][2], mx1 + pref[0][j]);
dp[i][j][2] = max(dp[i][j][2], mx2 + pref[0][j]);
}
}
ll sum = 0;
for(int j=0;j<=n;j++){
sum += pos[i+1][j];
ans = max(ans, dp[i][j][0] + sum);
ans = max(ans, dp[i][j][2] + sum);
}
}
return ans;
}
Compilation message
fish.cpp: In function 'll max_weight(int, int, std::vector<int>, std::vector<int>, std::vector<int>)':
fish.cpp:20:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
20 | for(int i=0;i<x.size();i++) pos[x[i]+1][y[i]+1] = w[i];
| ~^~~~~~~~~
/usr/bin/ld: /tmp/cccQqj7V.o: in function `main':
grader.cpp:(.text.startup+0x25e): undefined reference to `max_weights(int, int, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >)'
collect2: error: ld returned 1 exit status
