HDU3530 - Subsequence - 单调队列

1.题目描述：

Subsequence

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)
Total Submission(s): 6671    Accepted Submission(s): 2238

Problem Description

There is a sequence of integers. Your task is to find the longest subsequence that satisfies the following condition: the difference between the maximum element and the minimum element of the subsequence is no smaller than m and no larger than k.

 

Input

There are multiple test cases.
For each test case, the first line has three integers, n, m and k. n is the length of the sequence and is in the range [1, 100000]. m and k are in the range [0, 1000000]. The second line has n integers, which are all in the range [0, 1000000].
Proceed to the end of file.

 

Output

For each test case, print the length of the subsequence on a single line.

 

Sample Input

5 0 0 1 1 1 1 1 5 0 3 1 2 3 4 5

 

Sample Output

5 4

 

Source

2010 ACM-ICPC Multi-University Training Contest（10）——Host by HEU

 

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2.题意概述：

给出一个大小为n的数组a[n];

求其中最大值减最小值在[m,k]区间中的字串最长长度。

3.解题思路：

同样可以考虑在从左扫描的同时用单调栈维护当前最值，如果最值超过了就去掉队列前面的元素，至于是去最大值还是最小值应该贪心地去掉下标最小的那个元素。

去除得到合法解，如果区间值符合，就更新一下最值，注意初始化ans应该是0！

4.AC代码：

#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include