Submission #877125

#	Time	Username	Problem	Language	Result	Execution time	Memory
877125		MilosMilutinovic	Toy Train (IOI17_train)	C++14	100 / 100	482 ms	1884 KiB

train

#include "train.h"
#include <bits/stdc++.h>

using namespace std;

vector<int> who_wins(vector<int> a, vector<int> r, vector<int> u, vector<int> v) {
  int n = (int) a.size();
  int m = (int) u.size();
  vector<vector<int>> g(n);
  vector<vector<int>> t(n);
  for (int i = 0; i < m; i++) {
    g[u[i]].push_back(v[i]);
    t[v[i]].push_back(u[i]);
  }
  vector<bool> rem(n);
  auto CalcA = [&](vector<int> f) {
    vector<int> que = f;
    vector<int> deg(n);
    for (int i = 0; i < n; i++) {
      if (rem[i]) {
        continue;
      }
      if (a[i] == 0) {
        for (int j : g[i]) {
          if (!rem[j]) {
            deg[i] += 1;
          }
        }
      } else {
        deg[i] = 1;
      }
    }
    for (int x : que) {
      deg[x] = 0;
    }
    for (int b = 0; b < (int) que.size(); b++) {
      int x = que[b];
      for (int y : t[x]) {
        if (deg[y] <= 0) {
          continue;
        }
        deg[y] -= 1;
        if (deg[y] == 0) {
          que.push_back(y);
        }
      }
    }
    return que;
  };
  auto CalcB = [&](vector<int> f) {
    vector<int> que = f;
    vector<int> deg(n);
    for (int i = 0; i < n; i++) {
      if (rem[i]) {
        continue;
      }
      if (a[i] == 0) {
        deg[i] = 1;
      } else {
        for (int j : g[i]) {
          if (!rem[j]) {
            deg[i] += 1;
          }
        }
      }
    }
    for (int x : que) {
      deg[x] = 0;
    }
    for (int b = 0; b < (int) que.size(); b++) {
      int x = que[b];
      for (int y : t[x]) {
        if (deg[y] <= 0) {
          continue;
        }
        deg[y] -= 1;
        if (deg[y] == 0) {
          que.push_back(y);
        }
      }
    }
    return que;
  };
  vector<int> ans(n);
  while (true) {
    vector<int> c;
    for (int i = 0; i < n; i++) {
      if (r[i] == 1 && !rem[i]) {
        c.push_back(i);
      }
    }
    vector<int> v = CalcA(c);
    int cnt = 0;
    for (int i = 0; i < n; i++) {
      if (!rem[i]) {
        cnt += 1;
      }
    }
    if (v.size() == cnt) {
      for (int x : v) {
        ans[x] = 1;
      }
      break;
    }
    vector<bool> in(n);
    for (int x : v) {
      in[x] = true;
    }
    vector<int> vec;
    for (int i = 0; i < n; i++) {
      if (!rem[i] && !in[i]) {
        vec.push_back(i);
      }
    }
    vector<int> bad = CalcB(vec);
    for (int x : bad) {
      rem[x] = true;
    }
  }
  return ans;
}

Compilation message (stderr)

train.cpp: In function 'std::vector<int> who_wins(std::vector<int>, std::vector<int>, std::vector<int>, std::vector<int>)':
train.cpp:99:18: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   99 |     if (v.size() == cnt) {
      |         ~~~~~~~~~^~~~~~

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