Codeforces 672D

Posted 2021-03-15 thmyl

D. Robin Hood

time limit per test

1 second

memory limit per test

256 megabytes

input

standard input

output

standard output

We all know the impressive story of Robin Hood. Robin Hood uses his archery skills and his wits to steal the money from rich, and return it to the poor.

There are n citizens in Kekoland, each person has ci coins. Each day, Robin Hood will take exactly 1 coin from the richest person in the city and he will give it to the poorest person (poorest person right after taking richest‘s 1 coin). In case the choice is not unique, he will select one among them at random. Sadly, Robin Hood is old and want to retire in k days. He decided to spend these last days with helping poor people.

After taking his money are taken by Robin Hood richest person may become poorest person as well, and it might even happen that Robin Hood will give his money back. For example if all people have same number of coins, then next day they will have same number of coins too.

Your task is to find the difference between richest and poorest persons wealth after k days. Note that the choosing at random among richest and poorest doesn‘t affect the answer.

Input

The first line of the input contains two integers n and k (1 ≤ n ≤ 500 000, 0 ≤ k ≤ 109) — the number of citizens in Kekoland and the number of days left till Robin Hood‘s retirement.

The second line contains n integers, the i-th of them is ci (1 ≤ ci ≤ 109) — initial wealth of the i-th person.

Output

Print a single line containing the difference between richest and poorest peoples wealth.

Examples

input

Copy

4 1
1 1 4 2

output

Copy

2

input

Copy

3 1
2 2 2

output

Copy

0

Note

Lets look at how wealth changes through day in the first sample.

1. [1, 1, 4, 2]
2. [2, 1, 3, 2] or [1, 2, 3, 2]

So the answer is 3 - 1 = 2

In second sample wealth will remain the same for each person.

#include<iostream>
#include<cstdio>
#define maxn 500010
using namespace std;
int n,k,ans,mn,mx;
int a[maxn];
bool check1(int x){
    int t=k;
    for(int i=1;i<=n;i++){
        if(a[i]<x)t-=x-a[i];
        if(t<0)return 0;
    }
    return 1;
}
bool check2(int x){
    int t=k;
    for(int i=1;i<=n;i++){
        if(a[i]>x)t-=a[i]-x;
        if(t<0)return 0;
    }
    return 1;
}
int main(){
    scanf("%d%d",&n,&k);
    long long Sum=0;
    for(int i=1;i<=n;i++){
        scanf("%d",&a[i]);
        Sum+=a[i];
    }
    //二分最小值 
    int l=0,r=1000000000;
    while(l<=r){
        int mid=(l+r)>>1;
        if(check1(mid)){
            mn=mid;
            l=mid+1;
        }
        else r=mid-1;
    }
    
    l=0;r=1000000000;
    while(l<=r){
        int mid=(l+r)>>1;
        if(check2(mid)){
            mx=mid;
            r=mid-1;
        }
        else l=mid+1;
    }
//    cout<<mn<<‘ ‘<<mx<<endl;
    int ans;
    if(mn>=mx)ans=0;
    else ans=mx-mn;
    int mod=Sum%n;
    if(mod!=0&&ans==0)ans=1;
    printf("%d
",ans);
    return 0;
}