HK Maximum Subarray Sum

复杂度： O（nlogn）

#include<stdio.h>
#include<iostream>
#include<string.h>
#include<math.h>
#include<algorithm>
#include<queue>
#include<set>
#include<iterator>
#include<map>
using namespace std;
typedef unsigned long long ll;

int main()
{
    int t, n;
    ll m;
    scanf("%d", &t);
    ll maxm = 0;
    while(t--){
        scanf("%d", &n);
        pair<ll, int> a[n];
        scanf("%llu", &m);
        for(int i = 0; i < n; i++){
            scanf("%llu", &a[i].first);
            a[i].second = i + 1;    
        }
        a[0].first = a[0].first % m;
        ll maxm = a[0].first;
        for(int i = 1; i < n; i++){
            a[i].first = (a[i].first%m + a[i-1].first%m) % m;
            if(maxm < a[i].first) maxm = a[i].first;
        }   
        sort(a, a + n);
        ll minm = 1e15;
        for(int i = 0; i < n - 1; i++){
            if(a[i].second > a[i + 1].second){      
                if(minm > a[i+1].first - a[i].first){
                    minm = a[i+1].first - a[i].first;
                }   
            }
        }
        printf("%llu\n", max(maxm, m-minm));    
    }
    return 0;
}