HDU 3415 Max Sum of Max-K-sub-sequence

我用單調隊列做的，隊列內按區間和從大到小排列，則隊列頭到當前點的區間和最大，需要注意的是數組要開大一點不然wrong到哭啊。

#include <cstdio>
#include <cstring>
#include <string>
#include <iostream>
#include <map>
#include <vector>
#include <cmath>
#include <stack>
#include <queue>
#include <cstdlib>
#include <algorithm>
using namespace std;
typedef __int64 int64;
typedef long long ll;
#define M 100005
#define N 1000005
#define max_inf 0x7f7f7f7f
#define min_inf 0x80808080
#define mod 1000000007

int q[N];
int n , k , arr[N] , sum[N];

void Solve()
{
	int i , MAX = min_inf , len , spos;
	int front , rear;
	front = rear = 0;
	for (i = 1 ; i <= n+k ; i++)
	{
		while (rear > front && sum[i]-sum[q[rear-1]-1] < arr[i])rear--;
		q[rear++] = i;

		while (front < rear && i-q[front] >= k)front++;

		int temp = sum[i]-sum[q[front]-1];

		if (temp > MAX)
		{
			MAX = temp;
			len = i-q[front]+1;
			spos = q[front];
		}
		else if (temp == MAX && spos == q[front])
		{
			len = min(len , i-q[front]+1);
		}
	}
	int lpos = spos+len-1;
	if (lpos > n)lpos -= n;
	printf("%d %d %d\n",MAX , spos , lpos);
}

int main()
{
	int i , t;

	scanf("%d",&t);
	while (t--)
	{
		scanf("%d%d",&n,&k);
		for (sum[0] = 0 , i = 1 ; i <= n ; i++)
		{
			scanf("%d",arr+i);
			arr[n+i] = arr[i];
			sum[i] = sum[i-1]+arr[i];
		}
		for (i = n+1 ; i <= 2*n ; i++)sum[i] = sum[i-1]+arr[i];
		Solve();
	}
	return 0;
}