51nod 1065 最小正子段和

题目链接：51nod 1065 最小正子段和

房教说用前缀和做,然后看了别人博客懂了后就感觉,这个真有意思...

 #include<cstdio>
 #include<cstring>
 #include<algorithm>
 using namespace std;
 const int N = ;
 const int inf  = 0x3f3f3f3f;
 pair<long long, int> sum[N];
 int a[N];
 int n;
 int main(){
     int i, j;
     long long ans = inf;
     scanf("%d", &n);
     sum[] = make_pair(,);
     for(i = ; i <= n; ++i){
         scanf("%d", &a[i]);
         sum[i].first = a[i] + sum[i-].first;
         sum[i].second = i;
     }
     sort(sum+, sum++n);
     for(i = ; i <= n; ++i){
         if(sum[i].first > )
             ans = min(ans, sum[i].first);
         if(sum[i].second > sum[i-].second && sum[i].first > sum[i-].first)
             ans = min(ans, sum[i].first - sum[i-].first);
     }
     printf("%lld\n", ans);
     return ;
 }