<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:
        digits = list(str(num))
        hash_map = {int(digit): i for i, digit in enumerate(digits)}

        for i , digit in enumerate(digits):
            for j in range(9, int(digit), -1):
                if j in hash_map and hash_map[j] > i:
                    digits[i], digits[hash_map[j]] = digits[hash_map[j]], digits[i]
                    return int("".join(digits))
        
        return num


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