README.md

1144. Decrease Elements To Make Array Zigzag

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

Solutions (Rust)

1. Solution

impl Solution {
    pub fn moves_to_make_zigzag(nums: Vec<i32>) -> i32 {
        Self::moves_to_make_v(&nums, true).min(Self::moves_to_make_v(&nums, false))
    }

    fn moves_to_make_v(nums: &[i32], odd: bool) -> i32 {
        (odd as usize..nums.len())
            .step_by(2)
            .map(|i| {
                nums[i]
                    - nums[i]
                        .min(*nums.get(i - 1).unwrap_or(&1000) - 1)
                        .min(*nums.get(i + 1).unwrap_or(&1000) - 1)
            })
            .sum()
    }
}