Submission #1024561

#	Time	Username	Problem	Language	Result	Execution time	Memory
1024561		huutuan	Toy Train (IOI17_train)	C++14	27 / 100	854 ms	99412 KiB

train

#include "train.h"

#include <bits/stdc++.h>

using namespace std;

const int N=5010;
vector<int> g[N];
int d[N][N];

void bfs(int root){
   queue<int> q;
   q.push(root);
   while (q.size()){
      int u=q.front();
      q.pop();
      for (int v:g[u]) if (!d[root][v]){
         d[root][v]=1;
         q.push(v);
      }
   }
}

bool bfs2(int root, int n, vector<int> &r){
   if (r[root]) return 0;
   vector<int> dd(n);
   queue<int> q;
   q.push(root);
   while (q.size()){
      int u=q.front();
      q.pop();
      for (int v:g[u]) if (!dd[v] && !r[v]){
         dd[v]=1;
         q.push(v);
      }
   }
   return dd[root];
}

vector<int> who_wins(vector<int> a, vector<int> r, vector<int> u, vector<int> v) {
   int n=a.size(), m=u.size();
   bool sub1=1, sub3=1, sub4=1;
   for (int i=0; i<m; ++i) sub1&=u[i]==v[i] || u[i]+1==v[i];
   for (int i:a) sub3&=i, sub4&=!i;
   if (sub1){
      vector<int> ans(n), cyc(n);
      for (int i=0; i<m; ++i) if (u[i]==v[i]) cyc[u[i]]|=1; else cyc[u[i]]|=2;
      for (int i=n-1; i>=0; --i){
         if (cyc[i]==1){
            ans[i]=r[i];
         }else if (cyc[i]==2){
            ans[i]=ans[i+1];
         }else{
            if (a[i]) ans[i]=r[i] || ans[i+1];
            else ans[i]=r[i] && ans[i+1];
         }
      }
      return ans;
   }
   for (int i=0; i<m; ++i) g[u[i]].push_back(v[i]);
   for (int i=0; i<n; ++i) bfs(i);
   if (sub3){
      vector<int> ans(n);
      for (int i=0; i<n; ++i){
         for (int j=0; j<n; ++j) if (r[j]) ans[i]|=d[i][j] && d[j][j];
      }
      return ans;
   }
   if (sub4){
      vector<int> ans(n, 1);
      for (int i=0; i<n; ++i) if (bfs2(i, n, r)){
         for (int j=0; j<n; ++j) if (d[j][i]) ans[j]=0;
      }
      return ans;
   }
   return vector<int>(n, 0);
}

• Subtask 1: 5 / 5
• Subtask 2: 0 / 10
• Subtask 3: 11 / 11
• Subtask 4: 11 / 11
• Subtask 5: 0 / 12
• Subtask 6: 0 / 51