Codeforces Round #726 (Div. 2) A. Arithmetic Array

Posted 2021-06-29 issue是fw

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计算$sum=\sum _{i=1}^n{a}_i$

设添加了$x$个数,和为$f$

有$sum+f=n+x$

$x=sum-n+f$

$f\in [0,\inf ]$,显然取$0$最优,于是$x=sum-n$

然而$x$不能是负数,所以如果$sum-n$为负数的话答案是$1$

#include <bits/stdc++.h>
using namespace std;
const int mod = 1e9+7;
const int maxn = 3e5+10;
int n,t,a[maxn];
int main()
{
	int t; cin >> t;
	while( t-- )
	{
		scanf("%d",&n );
		int sum = 0;
		for(int i=1;i<=n;i++)	scanf("%d",&a[i] ), sum += a[i];
		if( sum-n<0 )	cout << 1 << endl;
		else	cout << sum-n << endl;
	}
	return 0;
}