感觉用二分更麻烦，这题用前缀和不是更简单么。

#include <bits/stdc++.h>
using namespace std;
#define ll long long
int n,ans;
int a[100005];
int main() {
	cin >> n;
	for(int i = 1,v;i <= n;i++) {
		scanf("%d",&v);
		a[i] += a[i-1]+v;//计算前缀和
		ans = min(ans,a[i]);
		//cout << a[i] << endl;
	}
	cout <<ans*-1+1;
    return 0;
}