A15211 | Luke is a Foodie
时间限制1s
内存限制256MB
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题目描述
Luke likes to eat. There are $n$ piles of food aligned in a straight line in front of him. The $i$ -th pile contains $a_i$ units of food.
Luke will walk from the $1$ -st pile towards the $n$ -th pile, and he wants to eat every pile of food without walking back. When Luke reaches the $i$ -th pile, he can eat that pile if and only if $|v - a_i| \leq x$ , where $x$ is a fixed integer, and $v$ is Luke's food affinity.
Before Luke starts to walk, he can set $v$ to any integer. Also, for each $i$ ( $1 \leq i \leq n$ ), Luke can change his food affinity to any integer before he eats the $i$ -th pile.
Find the minimum number of changes needed to eat every pile of food.
Note that the initial choice for $v$ is not considered as a change.
Luke will walk from the $1$ -st pile towards the $n$ -th pile, and he wants to eat every pile of food without walking back. When Luke reaches the $i$ -th pile, he can eat that pile if and only if $|v - a_i| \leq x$ , where $x$ is a fixed integer, and $v$ is Luke's food affinity.
Before Luke starts to walk, he can set $v$ to any integer. Also, for each $i$ ( $1 \leq i \leq n$ ), Luke can change his food affinity to any integer before he eats the $i$ -th pile.
Find the minimum number of changes needed to eat every pile of food.
Note that the initial choice for $v$ is not considered as a change.
输入格式
The input consists of multiple test cases. The first line contains a single integer $t$ ( $1 \leq t \leq 10^4$ ) — the number of test cases. The description of test cases follows.
For each test case, the first line contains two integers, $n, x$ ( $1 \leq n \leq 2 \cdot 10^5$ , $1 \leq x \leq 10^9$ ) — the number of piles, and the maximum difference between the size of a pile and Luke's food affinity, such that Luke can eat the pile.
The second line contains $n$ integers $a_1, a_2, \ldots , a_n$ ( $1 \leq a_i \leq 10^9$ ).
It is guaranteed that the sum of $n$ over all test cases does not exceed $2 \cdot 10^5$ .
For each test case, the first line contains two integers, $n, x$ ( $1 \leq n \leq 2 \cdot 10^5$ , $1 \leq x \leq 10^9$ ) — the number of piles, and the maximum difference between the size of a pile and Luke's food affinity, such that Luke can eat the pile.
The second line contains $n$ integers $a_1, a_2, \ldots , a_n$ ( $1 \leq a_i \leq 10^9$ ).
It is guaranteed that the sum of $n$ over all test cases does not exceed $2 \cdot 10^5$ .
输出格式
For each test case, output an integer on a separate line, which is the minimum number of changes needed.
输入输出样例
输入 #1
7 5 3 3 8 5 6 7 5 3 3 10 9 8 7 12 8 25 3 3 17 8 6 1 16 15 25 17 23 10 2 1 2 3 4 5 6 7 8 9 10 8 2 2 4 6 8 6 4 12 14 8 2 2 7 8 9 6 13 21 28 15 5 11 4 13 23 7 10 5 21 20 11 17 5 29 16 11
输出 #1
0 1 2 1 2 4 6
In the first test case, Luke can set $v$ to $5$ before he starts to walk. And he can walk straight to eat every piles of food without changing $v$ .
In the second test case, Luke can set $v$ to $3$ before he starts to walk. And he could change $v$ to $10$ before he eats the second pile. After that, he can walk straight to eat remaining food without changing $v$ .
In the fourth test case, Luke can set $v$ to $3$ before he starts to walk. And he could change $v$ to $8$ before he eats the sixth pile. After that, he can walk straight to eat remaining food without changing $v$ .
In the fifth test case, Luke can set $v$ to $4$ before he starts to walk. And he could change $v$ to $6$ before he eats the fourth pile. Then he could change $v$ to $12$ before he eats the seventh pile. After that, he can walk straight to eat remaining food without changing $v$ .
In the second test case, Luke can set $v$ to $3$ before he starts to walk. And he could change $v$ to $10$ before he eats the second pile. After that, he can walk straight to eat remaining food without changing $v$ .
In the fourth test case, Luke can set $v$ to $3$ before he starts to walk. And he could change $v$ to $8$ before he eats the sixth pile. After that, he can walk straight to eat remaining food without changing $v$ .
In the fifth test case, Luke can set $v$ to $4$ before he starts to walk. And he could change $v$ to $6$ before he eats the fourth pile. Then he could change $v$ to $12$ before he eats the seventh pile. After that, he can walk straight to eat remaining food without changing $v$ .
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评测结果：Accepted