Leetcode 670. Maximum Swap

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

1. Description

Maximum Swap

2. Solution

• Version 1

class Solution:
    def maximumSwap(self, num):
        s = list(str(num))
        length = len(s)
        if length < 2:
            return num

        for i in range(length - 1):
            max_index = i
            for j in range(i + 1, length):
                if s[j] >= s[max_index] and s[i] != s[j]:
                    max_index = j
            if max_index != i:
                temp = s[i]
                s[i] = s[max_index]
                s[max_index] = temp
                break 

        return int(''.join(s))

• Version 2

class Solution:
    def maximumSwap(self, num):
        s = list(str(num))
        length = len(s)
        if length < 2:
            return num

        pre = 0
        post = 0
        max_index = length - 1
        for i in range(length - 1, -1, -1):
            if s[i] > s[max_index]:
                max_index = i
            elif s[i] < s[max_index]:
                pre = i
                post = max_index


        temp = s[pre]
        s[pre] = s[post]
        s[post] = temp
        

        return int(''.join(s))

Reference

1. https://leetcode.com/problems/maximum-swap/