Educational Codeforces Round 85 (Rated for Div. 2)B. Middle Class

Many years ago Berland was a small country where only n people lived. Each person had some savings: the i-th one had ai burles.

The government considered a person as wealthy if he had at least x burles. To increase the number of wealthy people Berland decided to carry out several reforms. Each reform looked like that:

the government chooses some subset of people (maybe all of them);
the government takes all savings from the chosen people and redistributes the savings among the chosen people equally.
For example, consider the savings as list [5,1,2,1]: if the government chose the 1-st and the 3-rd persons then it, at first, will take all 5+2=7 burles and after that will return 3.5 burles to the chosen people. As a result, the savings will become [3.5,1,3.5,1].

A lot of data was lost from that time, so we don’t know how many reforms were implemented and to whom. All we can do is ask you to calculate the maximum possible number of wealthy people after several (maybe zero) reforms.

Input
The first line contains single integer T (1≤T≤1000) — the number of test cases.

Next 2T lines contain the test cases — two lines per test case. The first line contains two integers n and x (1≤n≤105, 1≤x≤109) — the number of people and the minimum amount of money to be considered as wealthy.

The second line contains n integers a1,a2,…,an (1≤ai≤109) — the initial savings of each person.

It’s guaranteed that the total sum of n doesn’t exceed 105.

Output
Print T integers — one per test case. For each test case print the maximum possible number of wealthy people after several (maybe zero) reforms.

Example
inputCopy
4
4 3
5 1 2 1
4 10
11 9 11 9
2 5
4 3
3 7
9 4 9
outputCopy
2
4
0
3

Note
The first test case is described in the statement.

In the second test case, the government, for example, could carry out two reforms: [11–––,9–,11,9]→[10,10,11–––,9–]→[10,10,10,10].

In the third test case, the government couldn’t make even one person wealthy.

In the fourth test case, the government could choose all people to carry out a reform: [9–,4–,9–]→[713,713,713].

題意

有n個人,每個人都有一定數量的錢,選出一部分人來將他們的錢平分,問在評分後的錢大於x的情況下,最多能選多少人

思路

優先選錢多的,
本來就大於x的一定選,然後再優先選取錢較多的才能實現最大
具體實現見代碼

代碼:

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
typedef long long ll;
const int N = 1e5 + 10;
int t;
ll a[N];
bool cmp(int x, int y)
{
    return x > y;
}
int main() 
{
    cin>>t;
    while (t--) 
    {
        ll n, x;
        cin>>n>>x;
        for (int i = 1; i <= n; ++i) 
           cin>>a[i];
        sort(a + 1, a + n + 1,cmp);//降序
        ll sum = 0;
        int ans = 0;
        for (int i = 1; i <= n; ++i) //判斷選取
        {
            sum += a[i];
            if (sum < x * i) 
                break;
            else 
                ans++;
        }
        printf("%d\n", ans);
    }
}

碼字不易,留個贊吧~

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