# 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`

``````class Solution {
public:
int movesToMakeZigzag(vector<int>& nums) {
int n = nums.size(), res[2] = {0, 0};
for (int i = 0; i < n; ++i) {
int left = i > 0 ? nums[i - 1] : 1001;
int right = i < n - 1 ? nums[i + 1] : 1001;
res[i % 2] += max(0, nums[i] - min(left, right) + 1);
}
return min(res[0], res[1]);
}
};
``````

Github 同步地址:

https://github.com/grandyang/leetcode/issues/1144

ZigZag Conversion

Binary Tree Zigzag Level Order Traversal

https://leetcode.com/problems/decrease-elements-to-make-array-zigzag/

https://leetcode.com/problems/decrease-elements-to-make-array-zigzag/discuss/350576/JavaC%2B%2BPython-Easy-and-concise

https://leetcode.com/problems/decrease-elements-to-make-array-zigzag/discuss/351306/C%2B%2B-O(n)-Brute-force-Easy-to-understand-and-detailed-explanation

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