// https://dashoj.com/p/89
#include <bits/stdc++.h>

#define N 1000010
using namespace std;

typedef long long ll;

ll n, m, ans; // 树木数量 需要木材总长度 答案
vector<ll> ls; // 输入长度列表

ll addd(int x) {
	ll re = 0;
	for (int i = 0; i < n; i++) if (ls[i] > x) re += ls[i] - x;
	return re;
}

int main() {
	ios::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
	cin >> n >> m;
	for (int i = 0; i < n; i++) {
		ll a;
		cin >> a;
		ls.push_back(a);
	}
	sort(ls.begin(), ls.end());
	ll l = 0, r = ls[n - 1];
	while (l <= r) {
		ll mid = (l + r) >> 1;
		if (addd(mid) < m) r = mid - 1;
		else {
			ans = mid;
			l = mid + 1;
		}
	}
	cout << ans << endl;
	return 0;
}

#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;
}

#include <iostream>
using namespace std;

int a[1000010];

int main() {
    cin.tie(0);
    cout.tie(0);

    long long n, m, max = -1, u = 0, x = 0;

    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
        if (max < a[i]) {
            max = a[i];
        }
    }

    long long l = 0, r = max;

    while (l <= r) {
        u = 0;
        int mid = (l + r) / 2;

        for (int i = 1; i <= n; i++) {
            if (a[i] > mid) {
                u += a[i] - mid;
            }
        }

        if (u >= m) {
            x = mid;
            l = mid + 1;
        } else {
            r = mid - 1;
        }
    }

    cout << x;
    return 0;
}

#include <bits/stdc++.h>
using namespace std;
const int N=1e6+10;
int n,m；
int a[N];

int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    int l=0,r=2e9;
    while(l<r){
        int mid=(l+r+1)/2;
        long long sum=0;
        for(int i=1;i<=n;i++){
            if(a[i]-mid>0) sum+=a[i]-mid;
        }
        if(sum>=m) l=mid;
        else r=mid-1;
    }
    cout<<l<<endl;
}

#include <bits/stdc++.h>
#define endl '\n'
using namespace std;
typedef pair<int,int> PII;  
using ll = long long;
using ULL = unsigned long long;
const int N = 1e6+5;

ll n ,m, a[N];

bool check(ll mid) {
    ll sum = 0;
    for (int i = 0; i < n; i++) 
        if (a[i] > mid) sum += a[i] - mid;
    return sum >= m;
}

inline void solve() { 
    cin >> n >> m;
    ll l = 0, r = 0;
    for (int i = 0; i < n; i++) {
        cin >> a[i];
        r = max(r,a[i]);
    }
    while (l < r) {
        ll mid = (l + r + 1) >> 1;
        if (check(mid)) l = mid;
        else r = mid -1;    
    }
    cout << l << endl;
}          

int main() { 
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    int _ = 1; 
    //int _; cin >> _;
    while (_--) solve();
    return 0;
}

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)

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;
}