Submission #606434

#	Time	Username	Problem	Language	Result	Execution time	Memory
606434		Sam_a17	Stations (IOI20_stations)	C++14	100 / 100	891 ms	844 KiB

stations

#include <bits/stdc++.h>
using namespace std;
 
#define sz(x) (int((x).size()))
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define dbg(x) cout << #x << " " << x << endl;
#define uniq(x) x.resize(unique(all(x)) - x.begin());
 
#define pb push_back
#define ld long double
#define ll long long
 
void pr(vector<int>& a) {
  cerr << "arr" << " ";
  for(auto i: a) {
    cerr << i << " "; 
  } cerr << endl;
}
 
 
vector<int> label(int n, int k, vector<int> u, vector<int> v) {
	vector<int> labels(n), in(n), depth(n), tin(n), tout(n);
  vector<int> adj[n + 1];
 
  int timer = 0;
  for(int i = 0; i < n - 1; i++) {
    in[u[i]]++, in[v[i]]++;
    adj[u[i]].push_back(v[i]);
    adj[v[i]].push_back(u[i]);
  }
 
  function<void(int node, int parent)> dfs;
  
  vector<int> compress;

  dfs = [&](int node, int parent) {
    tin[node] = timer++;

    for(auto i: adj[node]) {
      if(i == parent) continue;
      depth[i] = depth[node] + 1;
      dfs(i, node);
    }

    tout[node] = timer++;
  };
 

  dfs(0, -1);
 
  for(int i = 0; i < n; i++) {
    if(depth[i] % 2 == 0) {
      compress.push_back(tin[i]);
      labels[i] = tin[i];
    } else {
      compress.push_back(tout[i]);
      labels[i] = tout[i];
    }
  }

  sort(all(compress));

	for (int i = 0; i < n; i++) {
    labels[i] = lower_bound(all(compress), labels[i]) - compress.begin();
    tin[i] = tout[i] = 0;
    adj[i].clear();
	}
 
	return labels;
}
 
int find_next_station(int s, int t, std::vector<int> c) {

  if(sz(c) == 1) {
    return c[0];
  }

  int s_ti, s_tu;

  // pr(c);

  int size = sz(c);
  sort(all(c));

  bool t_in = false, t_out = false;

  if(s < c[0]) {
    s_ti = s;
    s_tu = c[size - 2];

    t_in = true;
  } else {
    s_tu = s;
    s_ti = c[1];

    t_out = true;
  }

  if(t >= s_ti && t <= s_tu) {
    // s's subtree
    if(t_in) {
      for(int i = 0; i < size; i++) {
        if(c[i] >= t) {
          return c[i];
        }
      }

      assert(false);
    } else {
      sort(rall(c));

      for(int i = 0; i < size; i++) {
        if(c[i] <= t) {
          return c[i];
        }
      }

      assert(false);
    }
  } else {
    if(t_in) {
      sort(all(c));
      return c.back();
    } else {
      sort(all(c));
      return c[0];
    }
  }

	return c[0];
}

Compilation message (stderr)

stations.cpp: In function 'int find_next_station(int, int, std::vector<int>)':
stations.cpp:87:22: warning: variable 't_out' set but not used [-Wunused-but-set-variable]
   87 |   bool t_in = false, t_out = false;
      |                      ^~~~~

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