A15880. Contrast Value
编程题
普及/提高-
知识点
题目描述
For an array of integers $[a_1, a_2, \dots, a_n]$ , let's call the value $|a_1-a_2|+|a_2-a_3|+\cdots+|a_{n-1}-a_n|$ the contrast of the array. Note that the contrast of an array of size $1$ is equal to $0$ .
You are given an array of integers $a$ . Your task is to build an array of $b$ in such a way that all the following conditions are met:
- $b$ is not empty, i.e there is at least one element;
- $b$ is a subsequence of $a$ , i.e $b$ can be produced by deleting some elements from $a$ (maybe zero);
- the contrast of $b$ is equal to the contrast of $a$ .
What is the minimum possible size of the array $b$ ?
You are given an array of integers $a$ . Your task is to build an array of $b$ in such a way that all the following conditions are met:
- $b$ is not empty, i.e there is at least one element;
- $b$ is a subsequence of $a$ , i.e $b$ can be produced by deleting some elements from $a$ (maybe zero);
- the contrast of $b$ is equal to the contrast of $a$ .
What is the minimum possible size of the array $b$ ?
输入格式
The first line contains a single integer $t$ ( $1 \le t \le 10^4$ ) — the number of test cases.
The first line of each test case contains a single integer $n$ ( $1 \le n \le 3 \cdot 10^5$ ) — the size of the array $a$ .
The second line contains $n$ integers $a_1, a_2, \cdot, a_n$ ( $0 \le a_i \le 10^9$ ) — elements of the array itself.
The sum of $n$ over all test cases doesn't exceed $3 \cdot 10^5$ .
The first line of each test case contains a single integer $n$ ( $1 \le n \le 3 \cdot 10^5$ ) — the size of the array $a$ .
The second line contains $n$ integers $a_1, a_2, \cdot, a_n$ ( $0 \le a_i \le 10^9$ ) — elements of the array itself.
The sum of $n$ over all test cases doesn't exceed $3 \cdot 10^5$ .
输出格式
For each test case, print a single integer — the minimum possible size of the array $b$ .
输入输出样例
输入 #1
4 5 1 3 3 3 7 2 4 2 4 1 1 1 1 7 5 4 2 1 0 0 4
输出 #1
2 2 1 3