第一种方法60pts

#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
using namespace std;
const int MaxN=1e6+10;
int a[MaxN];
int n,m;
long long cut_num(int mid)
{
    long long res=0;
    for(int i=1;i<=n;i++)
    {
        if(a[i]>mid)
            res+=a[i]-mid;
    }
    return res;
}
int main()
{
    cin>>n>>m;
    for(int i=1;i<=n;i++)
        scanf("%d",&a[i]);
    sort(a+1,a+1+n);
    int bottom=0;
    int top=a[n];
    while(bottom<top)
    {
        int mid=(bottom+top)/2;
        long long num= cut_num(mid);
        if(num>m)
        {
            bottom=mid+1;
        }
        else if(num<m)
        {
            top=mid-1;
        }
        else
        {
            bottom=mid;
            top=mid;
        }
    }
    cout<<bottom;
    return 0;
}

第二种就可以ac了

#include<iostream>
#include<algorithm>
#include<cstring>
#include<cmath>
using namespace std;
const int MaxN=1e6+10;
int a[MaxN];
int n,m;
long long cut_num(int mid)
{
    long long res=0;
    for(int i=1;i<=n;i++)
    {
        if(a[i]>mid)
            res+=a[i]-mid;
    }
    return res;
}
int main()
{
    cin>>n>>m;
    for(int i=1;i<=n;i++)
        scanf("%d",&a[i]);
    sort(a+1,a+1+n);
    int bottom=0;
    int top=a[n];
    while(bottom<=top)
    {
        int mid=(bottom+top)/2;
        long long num= cut_num(mid);
        if(num>=m)
        {
            bottom=mid+1;
        }
        else if(num<m)
        {
            top=mid-1;
        }
    }
    cout<<top;
    return 0;
}

没感觉有啥区别阿