public class Solution
extends Object
567 - Permutation in String\.
Medium
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.