#include <bits/stdc++.h>
#include "grader.h"
#define pb push_back
#define eb emplace_back
#define sz(x) (int)x.size()
#define all(x) x.begin(), x.end()
#define uniq(x) x.erase(unique(all(x)), x.end())
#define rall(x) x.rbegin(), x.rend()
//#define int long long
using namespace std;
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
const int mod = 1e9 + 7;
const int LOG = 20;
const int maxn = 1e5 + 5;
const double eps = 1e-9;
void setIO() {
ios_base::sync_with_stdio(false);
cin.tie(0);
cout.tie(0);
}
vector<vector<int> > graph;
vector<int> euler;
int timer = 0;
void dfs(int u, int p) {
euler[timer++] = u;
for(int &v : graph[u]) {
if(v == p) continue;
dfs(v, u);
}
}
// int ANS = 3;
// bool query(vector<int> v) {
// cout << "QUERY: ";
// for(int &x : v) cout << x << " ";
// cout << '\n';
// bool ans = false;
// for(int &x : v) if(x == ANS) ans = true;
// cout << "ANSWER: " << ans << '\n';
// return ans;
// }
int findEgg(int n, vector<pair<int, int> > edges) {
graph.clear();
euler.clear();
graph.resize(n+1);
euler.resize(n);
for(pair<int, int> &edge : edges) {
graph[edge.first].push_back(edge.second);
graph[edge.second].push_back(edge.first);
}
dfs(1, 0);
int ans = 0;
int l=0, r=n-1;
while(l <= r) {
if(l == r) return euler[l];
int mid = (l + r) / 2;
vector<int> to_query(euler.begin(), euler.begin() + mid + 1);
//cout << l+1 << " " << r+1 << " " << mid+1 << '\n';
if(query(to_query)) {
ans = mid;
r = mid - 1;
} else {
l = mid + 1;
}
}
return euler[ans];
}
int32_t main() {
setIO();
int n;
cin >> n;
vector<pii> edges(n-1);
for(int i=0; i<n-1; i++) {
int a, b;
cin >> a >> b;
edges[i] = {a, b};
}
cout << findEgg(n, edges) << '\n';
return 0;
}
Compilation message
/usr/bin/ld: /tmp/ccfl68TO.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/cc5uyseN.o:eastereggs.cpp:(.text.startup+0x0): first defined here
collect2: error: ld returned 1 exit status
