[Swift]LeetCode1144. 递减元素使数组呈锯齿状 | Decrease Eleme

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?微信公众号：山青咏芝（shanqingyongzhi）
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?原文地址：https://www.cnblogs.com/strengthen/p/11297773.html?
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Given an array?nums?of integers,a?move?consists of choosing any element and?decreasing it by 1.

An array?A?is a?zigzag array?if either:

• Every even-indexed element is greater than adjacent elements,ie.?A[0] > A[1] < A[2] > A[3] < A[4] > ...
• OR,every odd-indexed element is greater than adjacent elements,ie.?A[0] < A[1] > A[2] < A[3] > A[4] < ...

Return the minimum number of moves to transform the given array?nums?into a zigzag array.?

Example 1:

Input: nums = [1,2,3]
Output: 2
Explanation: We can decrease 2 to 0 or 3 to 1.

Example 2:

Input: nums = [9,6,1,2]
Output: 4?

Constraints:

• 1 <= nums.length <= 1000
• 1 <= nums[i] <= 1000

给你一个整数数组?nums，每次?操作?会从中选择一个元素并?将该元素的值减少?1。

如果符合下列情况之一，则数组?A?就是?锯齿数组：

• 每个偶数索引对应的元素都大于相邻的元素，即?A[0] > A[1] < A[2] > A[3] < A[4] > ...
• 或者，每个奇数索引对应的元素都大于相邻的元素，即?A[0] < A[1] > A[2] < A[3] > A[4] < ...

返回将数组?nums?转换为锯齿数组所需的最小操作次数。?

示例 1：

输入：nums = [1,3]
输出：2
解释：我们可以把 2 递减到 0，或把 3 递减到 1。

示例 2：

输入：nums = [9,2]
输出：4?

提示：

• 1 <= nums.length <= 1000
• 1 <= nums[i] <= 1000

 1 class Solution {
 2     func movesToMakeZigzag(_ nums: [Int]) -> Int {
 3         var n:Int = nums.count
 4         var j:Int = 0
 5         var s:Int = 0
 6         var t:Int = 0
 7         for i in stride(from:0,to:n,by:2)
 8         {
 9             j = 0
10             if i != 0
11             {
12                 j = max(j,nums[i]-nums[i-1]+1)
13             }
14             if i + 1 < n
15             {
16                 j = max(j,nums[i]-nums[i+1]+1)
17             }
18             s += j
19         }
20         for i in stride(from:1,by:2)
21         {
22             j = 0
23             if i != 0
24             {
25                 j = max(j,nums[i]-nums[i-1]+1)
26             }
27             if i + 1 < n
28             {
29                 j = max(j,nums[i]-nums[i+1]+1)
30             }
31             t += j
32         }
33         return min(s,t)       
34     }
35 }