Submission #933309

#	Time	Username	Problem	Language	Result	Execution time	Memory
933309		thunopro	Easter Eggs (info1cup17_eastereggs)	C++14	0 / 100	5 ms	10052 KiB

eastereggs

#include<bits/stdc++.h>
using namespace std ; 
#define maxn 200009
#define ll long long 
#define pb push_back 
#define fi first 
#define se second 
#define left id<<1
#define right id<<1|1 
#define re exit(0); 
#define _lower(x) lower_bound(v.begin(),v.end(),x)-v.begin()+1
const int mod = 1e9+7 ;
const int INF = 1e9 ; 
 
typedef vector<int> vi ; 
typedef pair<int,int> pii ; 
typedef vector<pii> vii ; 
 
template < typename T > void chkmin ( T &a , T b ) { if ( a > b ) a = b ; } 
template < typename T > void chkmax ( T &a , T b ) { if ( a < b ) a = b ; } 
 
void add ( int &a , int b ) 
{
	a += b ; 
	if ( a >= mod ) a -= mod ; 
	if ( a < 0 ) a += mod ; 
}
 
void rf () 
{
	freopen ("bai1.inp","r",stdin) ;
}
 
int _pow ( int a , int n ) 
{
	if ( n == 0 ) return 1 ; 
	int res = _pow (a,n/2) ; 
	if ( n % 2 ) return 1ll*res*res%mod*a%mod ; 
	else return 1ll*res*res%mod ; 
}
 
//int query ( vi v ) ; 
//int solve ( vi v ) ; 
//int findEgg ( int N , vii bridges ) ; 
//int main () 
//{
//	ios_base::sync_with_stdio(0); 
//	cin.tie(0);cout.tie(0); 
////	rf () ; 
//	int n ; 
//	vii bridges ; 
//	cin >> n ; 
//	for ( int i = 1 ; i < n ; i ++ ) 
//	{
//		int u , v ; cin >> u >> v ; 
//		bridges . pb ({u,v}) ; 
//	}
//	cout << findEgg (n,bridges) ; 
//}
//
//int query ( vi v ) 
//{
//	for ( auto x : v ) cerr << x << "\n" ; 
//	int z ; cin >> z ; 
//	return z ; 
//}
 
#include "grader.h"
int n ; vi adjList [maxn] ; 
vi L ; 
void dfs ( int u , int par = -1 ) 
{
	L . pb (u) ; 
	for ( auto v : adjList [u] )
	{
		if ( v == par ) continue ; 
		dfs (v,u) ; 
	}
}
 
int findEgg ( int N , vii bridges ) 
{
	n = N ; 
	for ( int i = 1 ; i <= n ; i ++ ) adjList[i].clear() ; 
	for ( auto x : bridges ) adjList[x.fi] . pb (x.se) , adjList[x.se] . pb (x.fi) ; 
	dfs (1) ; 
	int l = 0 , r = n-2 , res ; 
	while ( l <= r ) 
	{
		int mid = (l+r)/2 ; 
		if ( query(vi(L.begin(),L.end()+mid+1))) r = mid-1 , res = mid ; 
		else l = mid+1 ; 
	}
	return L[res] ; 
}

Compilation message (stderr)

eastereggs.cpp: In function 'void rf()':
eastereggs.cpp:31:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   31 |  freopen ("bai1.inp","r",stdin) ;
      |  ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
eastereggs.cpp: In function 'int findEgg(int, vii)':
eastereggs.cpp:94:14: warning: 'res' may be used uninitialized in this function [-Wmaybe-uninitialized]
   94 |  return L[res] ;
      |              ^

• Subtask 1: 0 / 40
• Subtask 2: 0 / 40
• Subtask 3: 0 / 20