Day 14 LeetCode

Day 14 Task:

2. Permutation in String: https://leetcode.com/problems/permutation-in-string/

💡

Explanation: https://www.youtube.com/watch?v=UbyhOgBN834

Solutions:

Please review all the solutions and try implementing on your own if you haven’t gotten it.

class Solution:
    def checkInclusion(self, s1: str, s2: str) -> bool:
        if(len(s2) < len(s1)):
            return False
        
        alp_1 = {}
        alp_2 = {}
        
        for i in range(26):
            alp_1[chr(97+i)] = 0
            alp_2[chr(97+i)] = 0
            
        for i in range(len(s1)):
            alp_1[s1[i]] += 1
            alp_2[s2[i]] += 1
            
        matches = 0
        
        for i in range(26):
            if(alp_1[chr(97+i)] == alp_2[chr(97+i)]):
                matches += 1
            
        l = 0
        for r in range(len(s1), len(s2)):
            if(matches == 26):
                return True
            alp_2[s2[l]] -= 1
            if(alp_2[s2[l]] == alp_1[s2[l]]):
                matches += 1
            elif(alp_1[s2[l]]-1 == alp_2[s2[l]]):
                matches -= 1
            l += 1
            
            alp_2[s2[r]] += 1
            if(alp_2[s2[r]] == alp_1[s2[r]]):
                matches += 1
            elif(alp_1[s2[r]] + 1 == alp_2[s2[r]]):
                matches -= 1
        if(matches == 26):
            return True
        return False