Submission #306080

#	Time	Username	Problem	Language	Result	Execution time	Memory
306080		eriksuenderhauf	Stations (IOI20_stations)	C++17	100 / 100	1047 ms	1280 KiB

stations

#include "stations.h"
#include <bits/stdc++.h>
using namespace std;

vector<int> label(int n, int k, vector<int> u, vector<int> v) {
  vector<int> deg(n);
  vector<vector<int>> adj(n);
  for (int i = 0; i < n - 1; i++)
    deg[u[i]]++, deg[v[i]]++, adj[u[i]].push_back(v[i]), adj[v[i]].push_back(u[i]);;
  vector<int> labels(n);
  function<void(int,int)> init = [&](int u, int p) {
    if (~p) adj[u].erase(find(adj[u].begin(), adj[u].end(), p));
    for (int v: adj[u])
      init(v, u);
  };
  init(0, -1);
  // function<void(int,int)> dfs;
  // function<void(int,int,int,int)> join = [&](int u, int l, int r, int v) {
  //   if (l > r) return;
  //   if (l == r)
  //     dfs(adj[u][l], 2*v+1);
  //   else {
  //     int m = (l+r) / 2;
  //     join(u, l, m, v*2+1);
  //     join(u, m+1, r, v*2+2);
  //   }
  // };
  // dfs = [&](int u, int l) {
  //   labels[u] = l;
  //   join(u, 0, adj[u].size()-1, l);
  // };
  int l = 0;
  function<void(int,int)> dfs = [&](int u, int d) {
    if (d == 0)
      labels[u] = l++;
    for (int v: adj[u])
      dfs(v, d ^ 1);
    if (d == 1)
      labels[u] = l++;
  };
  dfs(0, 0);
  return labels;
}

int find_next_station(int s, int t, vector<int> c) {
  sort(c.begin(), c.end());
  for (int i: c)
    if (i == t)
      return i;
  if (c.size() > 1) {
    if (s < c[0]) { // d = 0
      int l = s;
      for (int i = 0; i+1 < c.size(); i++) {
        if (l <= t && t <= c[i])
          return c[i];
        l = c[i];
      }
      return c.back();
    } else { // d = 1
      c.push_back(s);
      int l = c[1];
      for (int i = 2; i < c.size(); i++) {
        if (l <= t && t <= c[i])
          return l;
        l = c[i];
      }
    }
  }
  return c[0];
}

Compilation message (stderr)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:53:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   53 |       for (int i = 0; i+1 < c.size(); i++) {
      |                       ~~~~^~~~~~~~~~
stations.cpp:62:25: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   62 |       for (int i = 2; i < c.size(); i++) {
      |                       ~~^~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 8 / 8
• Subtask 3: 16 / 16
• Subtask 4: 10 / 10
• Subtask 5: 61 / 61