Submission #319387

#	Time	Username	Problem	Language	Result	Execution time	Memory
319387		shaf_wa_nur	Easter Eggs (info1cup17_eastereggs)	C++14	100 / 100	29 ms	508 KiB

eastereggs

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

using namespace std;

int findEgg(int n, vector<pair<int, int>> edges) {
  vector<vector<int>> g(n + 1);
  for (auto p : edges) {
    int u = p.first;
    int v = p.second;
    g[u].push_back(v);
    g[v].push_back(u);
  }
  vector<int> order;
  function<void(int, int)> dfs = [&](int u, int p) {
    order.push_back(u);
    for (int v : g[u]) {
      if (v != p) {
        dfs(v, u);
      }
    }
  };
  dfs(1, 0);
  int m = (int) order.size();
  int lo = 0, hi = m - 1;

  auto ok = [&](int x) {
    vector<int> c;
    for (int i = 0; i <= x; i++) {
      c.push_back(order[i]); 
    }
    return query(c);
  };
  while (lo < hi) {
    int mid = (lo + hi) / 2;
    if (ok(mid)) {
      hi = mid;
    }
    else {
      lo = mid + 1;
    }
  }
  return order[lo];
}

• Subtask 1: 40 / 40
• Subtask 2: 40 / 40
• Subtask 3: 20 / 20