[51NOD] 1065 最小正子段和

前缀和加SET维护 O(n + nlog(n))

结果不能为零 白下了一组数据...

set中的查找:
set<#>iterator it = ST.lower_bound(x);

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int MAXN = 1e6 + 10;

const ll INF =  2 * 0x3f3f3f3f;

ll ans = INF;

ll arr[MAXN] = {0}, brr[MAXN] = {0};

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0); 	cout.tie(0);
	
	set <ll> ST;

	int n;
	
	cin>>n;
	
	ST.insert(0);
	
	for(int i = 1; i <= n; ++i)
	{
		cin>>arr[i], brr[i] = arr[i] + brr[i - 1];
		
		//cout<<brr[i]<<'\n';
		if(arr[i] > 0)
			ans = min(ans, arr[i]);

		set <ll>::iterator it = ST.lower_bound(brr[i]);

		while(it == ST.end() || (brr[i] - *it) <= 0)
		{
			if(it == ST.begin())
				break;
			--it;
		}

		if(*it <= brr[i])
			ans = min(ans, brr[i] - *it);

		ST.insert(brr[i]);
	}

	cout<<ans<<'\n';

	return 0;
}