def get_wood_amount(trees, cut_height):
    # 计算砍下的木材总长度
    wood = sum(tree - cut_height for tree in trees if tree > cut_height)
    return wood

def find_max_height(trees, m):
    low, high = 0, max(trees)
    result = 0

    while low <= high:
        mid = (low + high) // 2
        wood = get_wood_amount(trees, mid)

        if wood >= m:
            result = mid
            low = mid + 1
        else:
            high = mid - 1

    return result

# 读取输入
n, m = map(int, input().split())
trees = list(map(int, input().split()))

# 计算结果
max_cut_height = find_max_height(trees, m)

# 输出结果
print(max_cut_height)

#include<bits/stdc++.h>
using namespace std;
using ll=long long;
int n;
const int N=1e6+5;
ll m,a[N];

bool check(ll mid){
    ll sum=0;
    for(int i=1;i<=n;i++){
        if(a[i]-mid<=0){//如果该树高<=砍树高度,直接跳过
            continue;
        }
        sum+=(a[i]-mid);
    }
    if(sum>=m){//当sum>=m说明砍树的高度要<=该mid
        return true;
    }
    return false;
}

int main(){
    cin>>n>>m;
    ll maxx=0;
    for(int i=1;i<=n;i++){
        cin>>a[i];
        maxx=max(maxx,a[i]);
    }
    sort(a+1,a+1+n);//先排序
    ll l=1,r=maxx,ans=0;
    while (r - l > 1) // 当右边界与左边界相差大于1时
	{
		int mid = (l + r) >> 1; // 取中间位置
		if (check(mid)){ // 如果满足条件
            ans=mid;//最后得到的mid就是答案
			l = mid; // 更新左边界为mid
        }
		else{
			r = mid; // 否则更新右边界为mid
	    }
    }
    cout<<ans<<endl;
    return 0;
}

普普通通二分题 我叫你开longlong你二龙嘛

#define _CRT_SECURE_NO_WARNINGS 1
/**
 * @brief 打开宏开关
 * */
#define _USE_MATH_DEFINES
#include <cmath>
#include <bits/stdc++.h>
using namespace std;
#define ll long long

const int N = 1e6 + 5;
ll n, m;
ll a[N];
bool bisearch(ll h)
{
	ll sum = 0;
	for (int i = 1; i <= n; i++)
	{
		if (a[i] > h) sum += a[i] - h;
	}
	return sum >= m;
}
int main()
{
	cin >> n >> m;
	for (int i = 1; i <= n; i++)
		cin >> a[i];
	ll l = 1, r = 1e9;
	while (l + 1 < r)
	{
		ll m = l + r >> 1;
		if (bisearch(m)) l = m;
		else r = m;
	}
	if (bisearch(l)) cout << l;
	else cout << r;
	return 0;
}

二分答案即可

#include <bits/stdc++.h>
using namespace std;
const int N = 1000010;
int a[N];
int n,m;
int mx = -1;
bool check(int x){
    long long sum = 0;
    for (int i = 1; i <= n; ++i) {
        if (a[i] > x) {
            sum += (a[i] - x);
        }else{
            continue;
        }
    }
    if (sum < m) return true;
    return false;
}
int main(){
    scanf("%d %d",&n,&m);
    for (int i = 1; i <= n; ++i) {
        scanf("%d",&a[i]);
        mx = max(mx,a[i]);
    }
    int l = 1,r = mx;
    while (l + 1 < r) {
        int mid = (l + r)/2;
        if (check(mid)) {
            r = mid;
        }else {
            l = mid;
        }
    }
    printf("%d\n",l);
    return 0;
}