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1144. Decrease Elements To Make Array Zigzag (Medium)

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 = [9,6,1,6,2]
Output: 4

 

Constraints:

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

Related Topics

[Array]

Hints

Hint 1

Do each case (even indexed is greater, odd indexed is greater) separately. In say the even case, you should decrease each even-indexed element until it is lower than its immediate neighbors.