3576. Transform Array to All Equal Elements
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You are given an integer array nums of size n containing only 1 and -1, and an integer k.
You can perform the following operation at most k times:
-
Choose an index
i(0 <= i < n - 1), and multiply bothnums[i]andnums[i + 1]by-1.
Note that you can choose the same index i more than once in different operations.
Return true if it is possible to make all elements of the array equal after at most k operations, and false otherwise.
Example 1:
Input: nums = [1,-1,1,-1,1], k = 3
Output: true
Explanation:
We can make all elements in the array equal in 2 operations as follows:
- Choose index
i = 1, and multiply bothnums[1]andnums[2]by -1. Nownums = [1,1,-1,-1,1]. - Choose index
i = 2, and multiply bothnums[2]andnums[3]by -1. Nownums = [1,1,1,1,1].
Example 2:
Input: nums = [-1,-1,-1,1,1,1], k = 5
Output: false
Explanation:
It is not possible to make all array elements equal in at most 5 operations.
Constraints:
1 <= n == nums.length <= 105nums[i]is either -1 or 1.1 <= k <= n
Hints
Hint 1
Try converting all elements to 1 and separately to -1. For each case, calculate the minimum number of operations needed.
Hint 2
Use a greedy approach: scan the array from left to right and apply an operation only when needed to fix mismatches.