Leetcode 2078. Two Furthest Houses With Different Colors

文章作者：Tyan
博客：noahsnail.com  |  CSDN  |  简书

1. Description

2. Solution

解析：Version 1，两层循环遍历，O(N^2)。

• Version 1

class Solution:
    def maxDistance(self, colors: List[int]) -> int:
        distance = 0
        length = len(colors)
        for i in range(length):
            for j in range(i+1, length):
                if colors[i] != colors[j]:
                    distance = max(distance, j - i)
        return distance

解析：Version 2，贪心算法，从右往左找与左边第一个不同颜色的房子，从左往右找与右边第一个不同颜色的房子，取距离最大的一个，O(N)。

• Version 2

class Solution:
    def maxDistance(self, colors: List[int]) -> int:
        distance = 0
        length = len(colors)
        for i in range(length-1, -1, -1):
            if colors[i] != colors[0]:
                distance = max(distance, i)
                break
        for i in range(length):
            if colors[i] != colors[length - 1]:
                distance = max(distance, length - 1 - i)
                break
        return distance

解析：Version 3，Version 2的另一个版本，通过一次循环完成，O(N)。

• Version 3

class Solution:
    def maxDistance(self, colors: List[int]) -> int:
        distance = 0
        length = len(colors)
        for index, color in enumerate(colors):
            if color != colors[0]:
                distance = max(distance, index)
            if color != colors[length-1]:
                distance = max(distance, length - 1 - index)
        return distance

Reference

1. https://leetcode.com/problems/two-furthest-houses-with-different-colors/