<p>You are given an integer <code>num</code>. You can swap two digits at most once to get the maximum valued number.</p>

<p>Return <em>the maximum valued number you can get</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> num = 2736
<strong>Output:</strong> 7236
<strong>Explanation:</strong> Swap the number 2 and the number 7.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> num = 9973
<strong>Output:</strong> 9973
<strong>Explanation:</strong> No swap.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>0 &lt;= num &lt;= 10<sup>8</sup></code></li>
</ul>

class Solution:
    def maximumSwap(self, num: int) -> int:
        num_list = list(str(num))
        ascend_flag = False
        tmp_max = float('-inf')
        tmp_max_idx = -1
        for i in range(len(num_list)):
            if not ascend_flag and i < len(num_list) - 1:
                if int(num_list[i]) < int(num_list[i+1]):
                    ascend_flag = True
            else:
                if int(num_list[i]) >= tmp_max:
                    tmp_max = int(num_list[i])
                    tmp_max_idx = i
        if not ascend_flag:
            return num
        for i in range(len(num_list)):
            if int(num_list[i]) < tmp_max:
                tmp = num_list[i]
                num_list[i] = str(tmp_max)
                num_list[tmp_max_idx] = tmp
                return int(''.join(num_list))
16400