<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 {
public:
    int maximumSwap(int num) {
        if(num<10) return num;

        int digit[10] = {0};
        int i=0, j;
        int n = num;
        while(n>0) {
            digit[i++] = n % 10;
            n /= 10;
        }
        n = i;
        i=n-1;
        while(i>0 && digit[i] >= digit[i-1] ) i--;
        if(i==0) return num;

        int md=0, mdId=0;
        for(j=i-1; j>=0; j--)
            if( md <= digit[j]) {
                md = digit[j];
                mdId = j;
            }
        for(j=n-1; j>=0; j--)
            if(md>digit[j]) break;    
        swap(digit[j], digit[mdId]);

        int maxN = 0;
        for(i=n-1; i>=0; i--)
            maxN = maxN*10 + digit[i];
        return maxN;    
    }
};
7300