Maximize Sum Of Array After K Negations

Similar Problems:

Given an array A of integers, we must modify the array in the following way: we choose an i and replace A[i] with -A[i], and we repeat this process K times in total. (We may choose the same index i multiple times.)

Return the largest possible sum of the array after modifying it in this way.

Example 1:

Input: A = [4,2,3], K = 1 Output: 5 Explanation: Choose indices (1,) and A becomes [4,-2,3].

Example 2:

Input: A = [3,-1,0,2], K = 3 Output: 6 Explanation: Choose indices (1, 2, 2) and A becomes [3,1,0,2].

Example 3:

Input: A = [2,-3,-1,5,-4], K = 2 Output: 13 Explanation: Choose indices (1, 4) and A becomes [2,3,-1,5,4].

Note:

- 1 <= A.length <= 10000
- 1 <= K <= 10000
- -100 <= A[i] <= 100

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.

- Solution:

// Blog link: https://code.dennyzhang.com/maximize-sum-of-array-after-k-negations // Basic Ideas: array + greedy // // Complexity: Time O(n*log(n)), Space O(1) import "sort" func largestSumAfterKNegations(A []int, K int) int { sort.Ints(A) for i, v := range A { if K<=0 || v >= 0 { break } A[i] = -A[i] K-- } minAbs := 1<<31-1 sum := 0 for _, v := range A { if v>=0 && v < minAbs { minAbs = v } sum += v } if K%2 == 1 { sum -= 2*minAbs } return sum }