# 1005. Maximize Sum Of Array After K Negations K 次取反后最大化的数组和

@TOC

## # 题目描述

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. 1 <= A.length <= 10000
2. 1 <= K <= 10000
3. -100 <= A[i] <= 100

## # 解题方法

### # 小根堆

Python代码如下：

class Solution(object):
def largestSumAfterKNegations(self, A, K):
"""
:type A: List[int]
:type K: int
:rtype: int
"""
_sum = sum(A)
heapq.heapify(A)
while K > 0:
curmin = heapq.heappop(A)
heapq.heappush(A, -curmin)
K -= 1
_sum += -curmin * 2;
return _sum

## # 日期

2019 年 3 月 10 日 —— 周赛进了第一页！