Submission #900407

#	Time	Username	Problem	Language	Result	Execution time	Memory
900407		nguyentunglam	Stations (IOI20_stations)	C++17	100 / 100	600 ms	10052 KiB

stations

#include "stations.h"
#include <vector>

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

const int N = 1e5 + 10;

int st[N], ed[N], t[N], f[N], order[N], timer;

vector<int> adj[N];

void dfs(int u, int p) {
  st[u] = ++timer;
  for(int &v : adj[u]) if (v != p) {
    t[v] = t[u] ^ 1;
    dfs(v, u);
  }
  ed[u] = timer;
  if (!t[u]) f[u] = st[u];
  else f[u] = ed[u];
}

std::vector<int> label(int n, int k, std::vector<int> u, std::vector<int> v) {
  for(int i = 0; i < n; i++) adj[i].clear(), st[i] = ed[i] = 0;

  for(int i = 0; i < u.size(); i++) {
    adj[u[i]].push_back(v[i]);
    adj[v[i]].push_back(u[i]);
  }

  timer = -1;
  dfs(0, -1);

//	if (st[0]) assert(0);
  for(int i = 0; i < n; i++) order[i] = i;

  sort(order, order + n, [] (const int &x, const int &y) {
    if (f[x] != f[y]) return f[x] < f[y];
    if (t[x] && t[y]) return st[x] > st[y];
    return t[x] < t[y];
       });

	vector<int> labels(n);

	timer = 0;

  for(int cur = 0; cur < n; cur++) {
    int i = order[cur];
    labels[i] = timer++;
  }


//  cout << st[3] << endl;

//	cout << "labels :"; for(int i = 0; i < n; i++) cout << labels[i] << " "; cout << endl;
////	cout << ed[1] << endl;
//	for(int i = 0; i < n; i++) cout << st[i] << " "; cout << endl;
//	for(int i = 0; i < n; i++) cout << ed[i] << " "; cout << endl;
////	cout << st[0] << endl;
//	cout << endl;
	return labels;
}

int find_next_station(int s, int t, std::vector<int> c) {
//  for(int &j : c) cout << j << " "; cout << endl;
  if (c.size() == 1) return c.back();
  if (!s) {
    for(int &v : c) if (v >= t) return v;
    assert(0);
  }
  if (s <= c[0]) { // st - ed
//    cout << 11 << endl;
    if (s <= t && t <= c.back()) {
      int ret = 1e9;
      for(int &v : c) if (v >= t) ret = min(ret, v);
      return ret;
    }
    return c.back();
  }
  else { // ed - st
//    cout << 22 << endl;
//    cout << c[1] << " " << s << " " << t << endl;
    if (c[1] <= t && t <= s) {
      int ret = 0;
      for(int &v : c) if (v <= t) ret = max(ret, v);
//      cout << ret << endl;
      return ret;
    }
    return c[0];
  }
}

Compilation message (stderr)

stations.cpp: In function 'std::vector<int> label(int, int, std::vector<int>, std::vector<int>)':
stations.cpp:27:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   27 |   for(int i = 0; i < u.size(); i++) {
      |                  ~~^~~~~~~~~~

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