2091. Removing Minimum and Maximum From Array

Medium

You are given a 0-indexed array of distinct integers nums.

There is an element in nums that has the lowest value and an element that has the highest value. We call them the minimum and maximum respectively. Your goal is to remove both these elements from the array.

A deletion is defined as either removing an element from the front of the array or removing an element from the back of the array.

Return the minimum number of deletions it would take to remove both the minimum and maximum element from the array.

Example 1:

Input: nums = [2,10,7,5,4,1,8,6]
Output: 5
Explanation: 
The minimum element in the array is nums[5], which is 1.
The maximum element in the array is nums[1], which is 10.
We can remove both the minimum and maximum by removing 2 elements from the front and 3 elements from the back.
This results in 2 + 3 = 5 deletions, which is the minimum number possible.

Example 2:

Input: nums = [0,-4,19,1,8,-2,-3,5]
Output: 3
Explanation: 
The minimum element in the array is nums[1], which is -4.
The maximum element in the array is nums[2], which is 19.
We can remove both the minimum and maximum by removing 3 elements from the front.
This results in only 3 deletions, which is the minimum number possible.

Example 3:

Input: nums = [101]
Output: 1
Explanation:  
There is only one element in the array, which makes it both the minimum and maximum element.
We can remove it with 1 deletion.

Constraints:

• 1 <= nums.length <= 10^5

• -10^5 <= nums[i] <= 10^5

• The integers in nums are distinct.

解題

func minimumDeletions(nums []int) int {
    if len(nums) == 1 { return 1 }
    
    // 三種可能：從頭刪除 從尾刪除 頭尾都刪一些
    maxi := 0 // 記錄值大的 index
    mini := 0 // 記錄值小的 index
    for i, n := range nums {
        if n > nums[maxi] { maxi = i }
        if n < nums[mini] { mini = i }
    }
    
    // 這個時候 maxi 代表 index 比較大的那個數，mini 代表 index 小的那個數
    // 反正兩個都要刪掉，不用管裡面存什麼
    if maxi < mini {
        mini, maxi = maxi, mini
    }
                // 從頭開始刪到 maxi // 從尾巴開始刪到 mini // 頭刪到 mini + 尾刪到 maxi
    return min(min(maxi + 1, len(nums) - mini), mini + 1 + len(nums) - maxi)
}

func min(a, b int) int {
    if a < b { return a }
    return b
}