AtCoder Beginner Contest 227 D 二分枚举答案

题目

题解思路

肯定是每次拿最大的K个数，优先队列T了。
我们枚举二分能操作的次数为P

具体证明看下面题解
参考题解
参考题解

AC代码

#include 
//#include 
//priority_queue
#define PII pair<int,int>
#define ll long long

using namespace std;

const  int  INF =  0x3f3f3f3f;
const  int N = 200010 ; 
long long  a[N] ; 
long long  n , k ,ans = 0  ; 
bool che(long long p)
{
    long long sum = 0 ; 
    for (int i = 1 ; i <= n ; i++ )
    {
        sum += min(a[i],p);
    }
    return sum >= p*k ;  
}
int main()
{
    ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
    cin >> n >> k ;
    for (int i = 1 ; i <= n ; i++ )
        cin >> a[i] ;
    long long t1 = 0 , t2 = 1e18/k ;
    while ( t1 < t2 )
    {
        long long mid = t2 + t1 + 1  >> 1 ;
        if (che(mid))
        {
            t1 = mid ;
        }else
            t2 = mid - 1 ;
    }
    cout << t1 << "\n" ; 
    return 0 ;
}