Submission #61981

#	Time	Username	Problem	Language	Result	Execution time	Memory
61981		minhcool	Easter Eggs (info1cup17_eastereggs)	C++17	100 / 100	76 ms	3108 KiB

eastereggs

#include<bits/stdc++.h>
#include "grader.h"
 
using namespace std;
 
#define pb push_back
#define fi first
#define se second
typedef pair<int, int> ii;
 
const int N = 1e5 + 5;
int a[N], cur;
vector<int> gr[N];
 
void dfs(int u, int p) {
    a[++cur] = u;
    for (int v : gr[u]) if(v != p) dfs(v, u);
}
 
int findEgg(int n, vector<ii> edge) {
    for (int i = 0; i < N; ++i) gr[i].clear();
    for (ii i : edge) {
        gr[i.fi].pb(i.se); gr[i.se].pb(i.fi);
    }
    dfs(1, 1);
 
    vector<int> ask;
    int l = 1, r = n;
 
    while(l < r) {
        int mid = l + r >> 1;
        ask.clear();
        for (int i = 1; i <= mid; ++i) ask.pb(a[i]);
        if(query(ask)) r = mid;
        else l = mid + 1;
    }
    return a[l];
}

Compilation message (stderr)

eastereggs.cpp: In function 'int findEgg(int, std::vector<std::pair<int, int> >)':
eastereggs.cpp:31:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
         int mid = l + r >> 1;
                   ~~^~~

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