Submission #873594

#	Time	Username	Problem	Language	Result	Execution time	Memory
873594		Ludissey	Catfish Farm (IOI22_fish)	C++17	14 / 100	1057 ms	2097152 KiB

fish

#include "fish.h"
#include <bits/stdc++.h>
#define int long long
using namespace std;

struct hash_pair {
    template <class T1, class T2>
    size_t operator()(const pair<T1, T2>& p) const
    {
        auto hash1 = hash<T1>{}(p.first);
        auto hash2 = hash<T2>{}(p.second);
 
        if (hash1 != hash2) {
            return hash1 ^ hash2;              
        }
         
        // If hash1 == hash2, their XOR is zero.
          return hash1;
    }
};

unordered_map<pair<int,int>, int, hash_pair> a;
vector<vector<int>> fsh;
vector<vector<int>> prfx;
 
map<pair<int,pair<int,int>>, int> memo;
int N,M;
//x N possible
//last 2N possible negatif et pas negatif
//big 2 possible
int dp(int x, int last, int big){
  if(memo.find({x,{last,big}})!=memo.end()) return memo[{x,{last,big}}];
  if(x==N) return 0;
 
  int mx = 0;
  for (auto i:fsh[x]) //O(N)
  {
    int c=0;
    if(i==0){
      if(last<=0) c=dp(x+1, 0, 1);
      else if(last>0) c=dp(x+1,(-last), 1);
    } else if(i>=abs(last)) {
      if(big==0) break;
      c=dp(x+1, i, 1);
    }else if(i<abs(last)){
      c=dp(x+1, i, 0);
    }
    if(x>0) {
      if(last>=0) {
        if(last<i&&i>0){  
          c+=prfx[x-1][i-1];
          if(last>0) c-=prfx[x-1][last-1];
        }
        if(i<last&&last>0){
          c+=prfx[x][last-1];
          if(i>0) c-=prfx[x][i-1];
        }
      }else{
        if(abs(last)<i&&i>0){
          c+=prfx[x-1][i-1];
          if(abs(last)>0) c-=prfx[x-1][abs(last)-1];
        }
      }
      
    }
    mx=max(c, mx);
  }
  return memo[{x,{last,big}}]=mx;
}
 
long long max_weights(signed n, signed m, std::vector<signed> X, std::vector<signed> Y, std::vector<signed> W) {
  N=n; M=m; 
  fsh.resize(N+1, vector<int>(1,0));
  prfx.resize(N+1, vector<int>(N+1,0));
  for (int i = 0; i < M; i++){
    a[{X[i],Y[i]}] = W[i];
    fsh[X[i]+1].push_back(Y[i]+1);
    if(X[i]>0) fsh[X[i]-1].push_back(Y[i]+1);
  }
  for (int i = 0; i < N; i++) sort(fsh[i].begin(),fsh[i].end()); // N log  N
  for (int i = 0; i < N; i++) //N*N
  {
    for (int j = 0; j < N; j++)
    {
      prfx[i][j]=a[{i,j}];
      if(j>0) prfx[i][j]+=prfx[i][j-1];
    }
  }
  int p=dp(0,0,1); //(N*2N*2*N) (300*600*300*2) (108.000.000)
  return p;
}

• Subtask 1: 0 / 3
• Subtask 2: 0 / 6
• Subtask 3: 0 / 9
• Subtask 4: 14 / 14
• Subtask 5: 0 / 21
• Subtask 6: 0 / 17
• Subtask 7: 0 / 14
• Subtask 8: 0 / 16