Codeforces Round #526 (Div. 2) B. Kvass and the Fair Nut(思维)

#include <bits/stdc++.h>
#define ll long long
using namespace std;
ll pre[1003];
ll n,s;

int main()
{
	ll Min = 0x3f3f3f3f3f, sum = 0;
	scanf("%lld%lld",&n,&s);
	for(int i=0;i<n;i++){
		scanf("%d",&pre[i]);
		Min = min(Min, pre[i]);
		sum += pre[i];
	}
	if(sum < s) puts("-1");
	else if(sum == s) puts("0");
	else{
		ll ans = 0;
		for(int i=0;i<n;i++){
			ans += abs(Min - pre[i]);
		}
		if(ans >= s){
			printf("%lld\n", Min);
		}
		else{
			ll xx = s - ans;
			ll yy = ceil(1.0 * xx / n);
			printf("%lld\n", Min - yy);
		}
	}
	return 0;
}

#include <bits/stdc++.h>
#define ll long long
#define  maxn 1005
using namespace std;
ll n,s;
ll pre[maxn];

bool Check(int xx){
  ll ans = 0;
  for(int i=0;i<n;i++){
    if(pre[i] < xx) return false;
    ans += (pre[i] - xx);
  }
  return ans >= s;
}

int main()
{
  scanf("%lld%lld",&n,&s);
  ll sum = 0;
  for(int i=0;i<n;i++){
    scanf("%d",&pre[i]);
    sum += pre[i];
  }
  if(sum < s){
    puts("-1");
    return 0;
  }
  ll l = 0, r = 1e9, mid;
  while(l <= r){
    mid = (l + r) >> 1;
    if(Check(mid)){
      l = mid + 1;
    }
    else r = mid - 1;
  }
  printf("%lld\n", l - 1);
  return 0;
}