[LeetCode] 567. Permutation in String

轉自LeetCode

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.

 

Example 1:

Input: s1 = "ab", s2 = "eidbaooo"
Output: true
Explanation: s2 contains one permutation of s1 ("ba").

Example 2:

Input: s1 = "ab", s2 = "eidboaoo"
Output: false

 

Constraints:

• 1 <= s1.length, s2.length <= 104
• s1 and s2 consist of lowercase English letters.

Solution

可以沿用 76. Minimum Window Substring 的想法

要找 permutation 其實就是要把 s1 的每個字元都用到

所以在這題，只要改一下終止條件就可以

只要找到 subsstring 的長度和 s1 一樣，就可以回傳 true

如果沒找到，就回傳 false

kotlin