Leetcode 670 Solution

This article provides solution to leetcode question 670 (maximum-swap)
Categories:
Tags:
Access this page by simply typing in "lcs 670" in your browser address bar if you have bunnylol configured.

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

Solution

class Solution:
    def maximumSwap(self, num: int) -> int:
        if num == 0:
            return 0

        a = []
        while num:
            a.append(num % 10)
            num //= 10
        a = list(reversed(a))

        b = [None] * len(a)
        for i in reversed(range(len(a))):
            if i == len(a) - 1:
                b[i] = (a[i], i)
            else:
                b[i] = max(b[i + 1], (a[i], i))

        for i in range(len(a)):
            j = b[i][1]

            if j == i or a[i] == a[j]:
                continue

            a[i], a[j] = a[j], a[i]
            break

        return int("".join([str(v) for v in a]))