<p>Given two strings <code>word1</code> and <code>word2</code>, return <em>the minimum number of <strong>steps</strong> required to make</em> <code>word1</code> <em>and</em> <code>word2</code> <em>the same</em>.</p>

<p>In one <strong>step</strong>, you can delete exactly one character in either string.</p>

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

<pre>
<strong>Input:</strong> word1 = &quot;sea&quot;, word2 = &quot;eat&quot;
<strong>Output:</strong> 2
<strong>Explanation:</strong> You need one step to make &quot;sea&quot; to &quot;ea&quot; and another step to make &quot;eat&quot; to &quot;ea&quot;.
</pre>

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

<pre>
<strong>Input:</strong> word1 = &quot;leetcode&quot;, word2 = &quot;etco&quot;
<strong>Output:</strong> 4
</pre>

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

<ul>
	<li><code>1 &lt;= word1.length, word2.length &lt;= 500</code></li>
	<li><code>word1</code> and <code>word2</code> consist of only lowercase English letters.</li>
</ul>

class Solution:
    def minDistance(self, word1: str, word2: str) -> int:
        unique = 0
        word1a = ''
        word2a = ''
        for char in word1:
            if not char in word2:
                unique += 1
            else:
                word1a += char
        for char in word2:
            if not char in word1:
                unique += 1
            else:
                word2a += char
        @cache
        def substeps(i, j):
            if i < 0:
                ret = max(0, j + 1)
            elif j < 0:
                ret = i + 1
            elif word1a[:i + 1] == word2a[:j + 1]:
                ret = 0
            elif word1a[i] == word2a[j]:
                ret = substeps(i - 1, j - 1)
            else:
                ret = min(substeps(i - 1, j - 1) + 2, substeps(i - 1, j) + 1, substeps(i, j - 1) + 1)
            #print(str(i) + " " + str(j)  + " " + word1a[:i + 1] + " " + word2a[:j + 1] + " " + str(ret))
            return ret
        return unique + substeps(len(word1a) - 1, len(word2a) - 1)
        
25386