Leetcode 1005. Maximize Sum Of Array After K Negations

数组操作算法

最新推荐文章于 2025-06-11 20:14:43 发布

转载最新推荐文章于 2025-06-11 20:14:43 发布 · 53 阅读

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原文链接：http://www.cnblogs.com/zywscq/p/10625197.html

本文介绍了一种算法，该算法通过对整数数组进行特定操作来最大化数组元素的总和。具体而言，可以翻转数组中K个负数来增加总和，并讨论了不同情况下如何实现最优解。

class Solution(object):
    def largestSumAfterKNegations(self, A, K):
        """
        :type A: List[int]
        :type K: int
        :rtype: int
        """
        have_zero = False
        negative = []
        positive = []
        for a in A:
            if a < 0:
                negative.append(a)
            elif a == 0:
                have_zero = True
            else:
                positive.append(a)
        neg_size = len(negative)
        if neg_size > 0:
            negative.sort()
            for i in range(neg_size):
                if K > 0:
                    negative[i] = -negative[i]
                    K -= 1
            if (K > 0) and (K % 2 == 1) and (not have_zero):
                positive.sort()
                if len(positive) > 0:
                    sub = min(positive[0], negative[neg_size - 1])
                else:
                    sub = negative[neg_size - 1]
                return sum(negative) + sum(positive) - 2 * sub
            return sum(negative) + sum(positive)
        elif have_zero:
            return sum(positive)
        else:
            K = K % 2
            if K == 1:
                positive.sort()
                positive[0] = -positive[0]
                return sum(positive)
            else:
                return sum(positive)