# 1521. Find a Value of a Mysterious Function Closest to Target

https://leetcode.com/problems/find-a-value-of-a-mysterious-function-closest-to-target

## Description

![](https://assets.leetcode.com/uploads/2020/07/09/change.png)

Winston was given the above mysterious function `func`. He has an integer array `arr` and an integer `target` and he wants to find the values `l` and `r` that make the value `|func(arr, l, r) - target|` minimum possible.

Return _the minimum possible value_ of `|func(arr, l, r) - target|`.

Notice that `func` should be called with the values `l` and `r` where `0 <= l, r < arr.length`.

**Example 1:**

```
**Input:** arr = [9,12,3,7,15], target = 5
**Output:** 2
**Explanation:** Calling func with all the pairs of [l,r] = [[0,0],[1,1],[2,2],[3,3],[4,4],[0,1],[1,2],[2,3],[3,4],[0,2],[1,3],[2,4],[0,3],[1,4],[0,4]], Winston got the following results [9,12,3,7,15,8,0,3,7,0,0,3,0,0,0]. The value closest to 5 is 7 and 3, thus the minimum difference is 2.
```

**Example 2:**

```
**Input:** arr = [1000000,1000000,1000000], target = 1
**Output:** 999999
**Explanation:** Winston called the func with all possible values of [l,r] and he always got 1000000, thus the min difference is 999999.
```

**Example 3:**

```
**Input:** arr = [1,2,4,8,16], target = 0
**Output:** 0
```

**Constraints:**

* `1 <= arr.length <= 105`
* `1 <= arr[i] <= 106`
* `0 <= target <= 107`

## ac

```java
```
