<p>An integer has <strong>monotone increasing digits</strong> if and only if each pair of adjacent digits <code>x</code> and <code>y</code> satisfy <code>x &lt;= y</code>.</p>

<p>Given an integer <code>n</code>, return <em>the largest number that is less than or equal to </em><code>n</code><em> with <strong>monotone increasing digits</strong></em>.</p>

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

<pre>
<strong>Input:</strong> n = 10
<strong>Output:</strong> 9
</pre>

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

<pre>
<strong>Input:</strong> n = 1234
<strong>Output:</strong> 1234
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> n = 332
<strong>Output:</strong> 299
</pre>

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

<ul>
	<li><code>0 &lt;= n &lt;= 10<sup>9</sup></code></li>
</ul>

class Solution {
public:
    int monotoneIncreasingDigits(int n) {
    string s = to_string(n);
    int length = s.length();
    int mark = length;
    
    for (int i = length - 1; i > 0; --i) {
        if (s[i] < s[i - 1]) {
            --s[i - 1];
            mark = i;
        }
    }
    
    for (int i = mark; i < length; ++i) {
        s[i] = '9';
    }
    
    return stoi(s);
}

};
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