Submission #788433

#	Time	Username	Problem	Language	Result	Execution time	Memory
788433		NeroZein	Toy Train (IOI17_train)	C++17	0 / 100	7 ms	2132 KiB

train

#include "train.h"
#include "bits/stdc++.h"
using namespace std;

std::vector<int> who_wins(std::vector<int> a, std::vector<int> r, std::vector<int> U, std::vector<int> V) {
  int n = (int) a.size(); 
  int m = (int) U.size(); 
  vector<vector<int>> g(n);
  vector<vector<int>> rg(n);
  for (int i = 0; i < m; ++i) {
    g[U[i]].push_back(V[i]);
    rg[V[i]].push_back(U[i]);
  }
  vector<int> stk; 
  vector<int> vis(n); 
  function<void(int)> dfs = [&](int v) {
    vis[v] = 1; 
    for (int u : g[v]) {
      if (!vis[u]) {
        dfs(u); 
      }
    }
    stk.push_back(v);
  };
  for (int i = 0; i < n; ++i) {
    if (!vis[i]) {
      dfs(0);      
    }
  }
  set<pair<int, int>> se; 
  int ncc = 0; 
  function<void(int)> dfs2 = [&](int v) {
    vis[v] = ncc; 
    for (int u : rg[v]) {
      if (vis[u] == -1) {
        dfs2(u);  
      } else if (vis[u] != ncc) {
        se.emplace(vis[u], ncc); 
      }
    }
  }; 
  fill(vis.begin(), vis.end(), -1); 
  for (int i = n - 1; i >= 0; --i) {
    if (vis[stk[i]] == -1) {
      dfs2(stk[i]); 
      ncc++; 
    }
  }
  vector<bool> win(ncc);
  for (int i = 0; i < n; ++i) {
    if (r[i]) {
      win[vis[i]] = true; 
    }
  }
  vector<vector<int>> sccg(ncc); 
  for (auto it : se) {
    sccg[it.first].push_back(it.second); 
  }
  vector<int> dp(ncc, -1); 
  function<int(int v)> dfs3 = [&](int v) -> int{
    int& ret = dp[v];
    if (ret != -1) {
      return ret;
    }
    ret = win[v];
    for (auto u : sccg[v]) {
      ret |= dfs3(u); 
    }
    return ret; 
  };
  for (int i = 0; i < ncc; ++i) {
    dfs3(i);
  }
  vector<int> res(n); 
  for (int i = 0; i < n; ++i) {
    //cout << vis[i] << ' ';
    res[i] = dp[vis[i]]; 
  }
  //cout << '\n';
  return res;
}

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