# Maximum Swap

Given a non-negative integer, you could swap two digits**at most**once to get the maximum valued number. Return the maximum valued number you could get.

**Example 1:**

```
Input:
 2736

Output:
 7236

Explanation:
 Swap the number 2 and the number 7.
```

**Example 2:**

```
Input:
 9973

Output:
 9973

Explanation:
 No swap.
```

**Note:**

1. The given number is in the range \[0, 108]

分析

排序数组和原数组比较 第一个小于sort的就是需要交换的。记得从右边起找到第一个换，同时要break

最左的小数和最右的大数交换

```
class Solution:
    def maximumSwap(self,num):
        """
        :type num: int
        :rtype: int
        """
        nums = list(map(int, str(num)))
        sorted_nums = sorted(nums, reverse=True)
        n = len(nums)
        for i in range(n):
            if nums[i] < sorted_nums[i]:
                idx = n - 1 - nums[::-1].index(sorted_nums[i])
                nums[idx], nums[i] = nums[i], nums[idx]
                break;
        return int(''.join(map(str, nums)))
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://nataliekung.gitbook.io/ladder_code/facebook/maximum-swap.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.