【leetcode】1432. Max Difference You Can Get From Changing an Integer

标签：col   代码   最大值   nat   result   for   lead   ros   第一个   

题目如下：

You are given an integer num. You will apply the following steps exactly two times:

• Pick a digit x (0 <= x <= 9).
• Pick another digit y (0 <= y <= 9). The digit y can be equal to x.
• Replace all the occurrences of x in the decimal representation of num by y.
• The new integer cannot have any leading zeros, also the new integer cannot be 0.

Let a and b be the results of applying the operations to num the first and second times, respectively.

Return the max difference between a and b.

Example 1:

Input: num = 555
Output: 888
Explanation: The first time pick x = 5 and y = 9 and store the new integer in a.
The second time pick x = 5 and y = 1 and store the new integer in b.
We have now a = 999 and b = 111 and max difference = 888

Example 2:

Input: num = 9
Output: 8
Explanation: The first time pick x = 9 and y = 9 and store the new integer in a.
The second time pick x = 9 and y = 1 and store the new integer in b.
We have now a = 9 and b = 1 and max difference = 8

Example 3:

Input: num = 123456
Output: 820000

Example 4:

Input: num = 10000
Output: 80000

Example 5:

Input: num = 9288
Output: 8700

Constraints:

• 1 <= num <= 10^8

解题思路：最大值很好求，把第一个不是9的数字替换成9即可。最小值分两种情况，如果最高位不为1，那么替换成1；否则，找出第一个不为0的数字替换成0。

代码如下：

class Solution(object):
    def maxDiff(self, num):
        """
        :type num: int
        :rtype: int
        """
        str_num = str(num)
        max_replace = ‘9‘
        min_replace = ‘0‘
        for i in str_num:
            if i != ‘9‘:
                max_replace = i
                break

        replace_val = ‘0‘
        if str_num[0] != ‘1‘:
            min_replace = str_num[0]
            replace_val = ‘1‘
        else:
            for i in str_num:
                if i != ‘0‘ and i != str_num[0]:
                    min_replace = i
                    break

        max_num = str_num.replace(max_replace,‘9‘)
        min_num = str_num.replace(min_replace,replace_val)
        return int(max_num) - int(min_num)

【leetcode】1432. Max Difference You Can Get From Changing an Integer

标签：col   代码   最大值   nat   result   for   lead   ros   第一个   

原文地址：https://www.cnblogs.com/seyjs/p/13040510.html