LeetCode 1005. Maximize Sum Of Array After K Negations

Description

https://leetcode.com/problems/maximize-sum-of-array-after-k-negations/

Given an array nums of integers, we must modify the array in the following way: we choose an i and replace nums[i] with -nums[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: nums = [4,2,3], k = 1
Output: 5
Explanation: Choose indices (1,) and nums becomes [4,-2,3].

Example 2:

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

Example 3:

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

Note:

  1. 1 <= nums.length <= 10000
  2. 1 <= k <= 10000
  3. -100 <= nums[i] <= 100

Explanation

For each time of negation, change the minimum number.

Python Solution

class Solution:
    def largestSumAfterKNegations(self, A: List[int], K: int) -> int:
                
        while K > 0:            
            min_num = min(A)            
            min_num_index = A.index(min_num)
            
            A[min_num_index] = -min_num
                                    
            K -= 1        
        
        return sum(A)
  • Time Complexity: O(N).
  • Space Complexity: O(1).

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