[Leet Code] Find and Replace Pattern

Matthew Boyd
2 min readSep 19, 2021

Leet code: https://leetcode.com/problems/find-and-replace-pattern/

Problem:

Given a list of strings words and a string pattern, return a list of words[i] that match pattern. You may return the answer in any order.

A word matches the pattern if there exists a permutation of letters p so that after replacing every letter x in the pattern with p(x), we get the desired word.

Recall that a permutation of letters is a bijection from letters to letters: every letter maps to another letter, and no two letters map to the same letter.

Example 1:

Input: words = ["abc","deq","mee","aqq","dkd","ccc"], pattern = "abb"
Output: ["mee","aqq"]
Explanation: "mee" matches the pattern because there is a permutation {a -> m, b -> e, ...}.
"ccc" does not match the pattern because {a -> c, b -> c, ...} is not a permutation, since a and b map to the same letter.

Example 2:

Input: words = ["a","b","c"], pattern = "a"
Output: ["a","b","c"]

Constraints:

  • 1 <= pattern.length <= 20
  • 1 <= words.length <= 50
  • words[i].length == pattern.length
  • pattern and words[i] are lowercase English letters.

Solution:

class Solution(object):
def findAndReplacePattern(self, words, pattern):
"""
:type words: List[str]
:type pattern: str
:rtype: List[str]
"""
testing = {}
testing_2 = []
incrementer = 1
for i in pattern:
if i not in testing:
testing[i] = incrementer
testing_2.append(incrementer)
incrementer += 1
else:
testing_2.append(testing[i])

print(testing_2)


print testing
answers = []
for i in words:
comparison = {}
comparison_2 = []
incrementer = 1
for j in i:
if j not in comparison:
comparison[j] = incrementer
comparison_2.append(incrementer)
incrementer += 1
else:
comparison_2.append(comparison[j])
if testing_2 == comparison_2:
answers.append(i)


return answers

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