改成longlong就過了

這題是找最大的，最初寫成找最小的了，也就是r當答案了

AC Code

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int maxn = 1e6+10;
const int INF = 0x3f3f3f3f;
ll t[maxn],n,m;
bool solve(int mid) {
	ll sum =0;
	for(int i=0; i<n; i++) {
		if(t[i] > mid)
			sum+=(t[i] - mid);
	}
	return sum>=m;
}
int main() {
	ll mmax=0;
	cin>>n>>m;
	for(int i=0; i<n; i++) {
		cin>>t[i];
		mmax = max(mmax,t[i]);
	}
	ll l=0,r=mmax,mid,ans = 0;
	while(l<=r) {
		mid = (r+l)/2;
		if(!solve(mid)) 
			r = mid-1;
		else 
			l = mid+1 ;
	}
	cout<<l-1<<endl;
	return 0;
}
 

Other 

    sort(h+1,h+n+1);
    l=0;
    r=h[n];
    while (l+1<r)
    {
        ll maxn=0;
        mid=(l+r)/2;
        for (int i=1;i<=n;i++)
        if (h[i]>mid) maxn=maxn+h[i]-mid;
        if (maxn<m) r=mid;
        else l=mid;
    }
    printf("%lld",l);