Submission #535062

#	Time	Username	Problem	Language	Result	Execution time	Memory
535062		chenwz	Stations (IOI20_stations)	C++14	100 / 100	1091 ms	676 KiB

stations

#include "stations.h"
#include <vector>
#include <algorithm>
using namespace std;
typedef vector<int> VI;

void dfs(int u, int fa, bool dfs_in, int &clock, const vector<VI>& G, VI& L) {
  if (dfs_in) L[u] = clock++;
  for (int i : G[u])
    if (i != fa) dfs(i, u, !dfs_in, clock, G, L);
  if (!dfs_in) L[u] = clock++;
}

VI label(int n, int k, VI u, VI v) {
  VI L(n);
  vector<VI> G(n, VI());
  for (size_t i = 0; i < u.size(); i++)
    G[u[i]].push_back(v[i]), G[v[i]].push_back(u[i]);
  int clock = 0;
  dfs(0, -1, true, clock, G, L);
  return L;
}

int find_next_station(int s, int t, VI c) {
  int c0 = c[0];
  if (c0 > s) { // Case 1: s is Tin. All the neighbors' label > s.
    if (t < s || t > c.back()) return c.back(); // t not in this subtree, go to parent.
    return *lower_bound(c.begin(), c.end(), t); // t is in this subtree, Pick the smallest ch >= t
  }
  // Case 2: s is Tout level.
  if (t < c0 || t > s)  return c0; // t not in subtree, go to root
  return *(upper_bound(c.begin(), c.end(), t) - 1); // last v that <= t
}

// int main(){
//   return 0;
// }

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