<p>A binary string is monotone increasing if it consists of some number of <code>0</code>'s (possibly none), followed by some number of <code>1</code>'s (also possibly none).</p>
<p>You are given a binary string <code>s</code>. You can flip <code>s[i]</code> changing it from <code>0</code> to <code>1</code> or from <code>1</code> to <code>0</code>.</p>
<p>Return <em>the minimum number of flips to make </em><code>s</code><em> monotone increasing</em>.</p>