## DEV Community

Abhishek Chaudhary

Posted on

# Delete Operation for Two Strings

Given two strings `word1` and `word2`, return the minimum number of steps required to make `word1` and `word2` the same.

In one step, you can delete exactly one character in either string.

Example 1:

Input: word1 = "sea", word2 = "eat"
Output: 2
Explanation: You need one step to make "sea" to "ea" and another step to make "eat" to "ea".

Example 2:

Input: word1 = "leetcode", word2 = "etco"
Output: 4

Constraints:

• `1 <= word1.length, word2.length <= 500`
• `word1` and `word2` consist of only lowercase English letters.

SOLUTION:

``````class Solution:
def md(self, word1, word2, i1, i2):
if (i1, i2) in self.cache:
return self.cache[(i1, i2)]
if i1 == len(word1):
return len(word2) - i2
if i2 == len(word2):
return len(word1) - i1
if word1[i1] == word2[i2]:
self.cache[(i1, i2)] = min(self.md(word1, word2, i1 + 1, i2 + 1), 1 + self.md(word1, word2, i1, i2 + 1), 1 + self.md(word1, word2, i1 + 1, i2))
return self.cache[(i1, i2)]
else:
self.cache[(i1, i2)] = 1 + min(self.md(word1, word2, i1, i2 + 1), self.md(word1, word2, i1 + 1, i2))
return self.cache[(i1, i2)]

def minDistance(self, word1: str, word2: str) -> int:
self.cache = {}
return self.md(word1, word2, 0, 0)
``````