#567

Permutation in String

medium· Sliding Windowruns: 0

Given two strings s1 and s2, return true if s2 contains a permutation of s1, or false otherwise. In other words, return true if one of s1's permutations is the substring of s2.

wpm 0acc 100%time 0:000 / 607

class Solution:
    def checkInclusion(self, s1: str, s2: str) -> bool:
        if len(s1) > len(s2):
            return False
        s1_count = [0] * 26
        s2_count = [0] * 26
        for i in range(len(s1)):
            s1_count[ord(s1[i]) - ord("a")] += 1
            s2_count[ord(s2[i]) - ord("a")] += 1
        if s1_count == s2_count:
            return True
        for i in range(len(s1), len(s2)):
            s2_count[ord(s2[i]) - ord("a")] += 1
            s2_count[ord(s2[i - len(s1)]) - ord("a")] -= 1
            if s1_count == s2_count:
                return True
        return False

click the box to focus · tab inserts 4 spaces · backspace to correct · esc to pause

desktop only

codedrill is a typing game and needs a real keyboard. open this on a laptop or desktop to practice.

you can still browse problems and sections from your phone.