| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1168496 | jj_master | Catfish Farm (IOI22_fish) | C++20 | 0 ms | 0 KiB |
#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define eb emplace_back
#define fi first
#define se second
#define ins insert
int max_weights(int N, int M, vector<int> &X, vector<int> &Y, vector<int> &W)
{
vector DP(N+1, vector(2,0ll));
vector<vector<pair<int, long long>>> pref(N+2);
for(int i=0;i<=N+1;i++) pref[i].emplace_back(0,0);
vector<vector<int>> sp(N+2);
for(int i=1;i<=N+1;i++)sp[i].emplace_back(0);
for(int i=1;i<=N+1;i++)sp[i].emplace_back(N);
vector t1(2,vector(N+1,0ll));
vector t2(3,vector(N+1,0ll));
vector t3(3,vector(N+1,0ll));
vector t4(2,vector(N+1,0ll));
for(int i=0;i<M;i++) {
pref[X[i]+1].emplace_back(Y[i]+1,W[i]);
sp[X[i]+1].emplace_back(Y[i]);
}
for(int i=1;i<=N+1;i++) {
sort(sp[i].begin(),sp[i].end());
sp[i].erase(unique(sp[i].begin(),sp[i].end()),sp[i].end());
sort(pref[i].begin(), pref[i].end());
for(int j=1;j<pref[i].size();j++)pref[i][j].second+=pref[i][j-1].second;
}
auto getpref = [&](int i,int j) {
auto iter = lower_bound(pref[i].begin(),pref[i].end(),make_pair(j+1,-1ll));
iter--;
return iter->second;
};
auto get_higher = [&](int i,int j) {
return lower_bound(sp[i].begin(),sp[i].end(),j)-sp[i].begin()-0;
};
auto get_lower = [&](int i,int j) {
return upper_bound(sp[i].begin(),sp[i].end(),j)-sp[i].begin()-1;
};
for(int i=2;i<=N;i++) {
int tot = sp[i].size()-1;
for(int s=0;s<=tot;s++) {
int j = sp[i][s];
if(i!=2)DP[s][1]=max(DP[s][1],-getpref(i,j)+t1[0][get_higher(i-1,j)]);
else DP[s][1]=max(DP[s][1],getpref(i,N)-getpref(i,j));
if(i>2) {
if(i!=3) {
DP[s][0]=max(DP[s][0],getpref(i-1,j)+t2[0][get_lower(i-2,j)]);
DP[s][0]=max(DP[s][0],t3[0][get_higher(i-2,j)]);
}
else DP[s][0]=max(DP[s][0],getpref(i-1,N));
}
if(i!=2)DP[s][0]=max(DP[s][0],getpref(i-1,j)+t4[0][get_lower(i-1,j)]);
else DP[s][0]=max(DP[s][0],getpref(i-1,j));
t1[1][s]=getpref(i+1,j)+max(DP[s][0],DP[s][1]);
t2[2][s]=max(DP[s][0],DP[s][1]);
t3[2][s]=getpref(i+1,j)+max(DP[s][0],DP[s][1]);
t4[1][s]=-getpref(i,j)+DP[s][0];
}
for(int j=tot-1;j>=0;j--)t1[1][j]=max(t1[1][j],t1[1][j+1]);
for(int j=1;j<=tot;j++)t2[2][j]=max(t2[2][j],t2[2][j-1]);
for(int j=tot-1;j>=0;j--)t3[2][j]=max(t3[2][j],t3[2][j+1]);
for(int j=1;j<=tot;j++)t4[1][j]=max(t4[1][j],t4[1][j-1]);
swap(t1[0], t1[1]);
swap(t2[0], t2[1]);
swap(t2[1], t2[2]);
swap(t3[0], t3[1]);
swap(t3[1], t3[2]);
swap(t4[0], t4[1]);
}
long long ans = 0;
for(int j = 0; j <= N; j++) ans = max(ans, DP[j][0]);
for(int j=0; j <= N; j++) ans = max(ans, DP[j][1]);
return ans;
}