排列

567. Permutation in String

Given two strings s1 and s2, write a function to return true if s2 contains the permutation of s1. In other words, one of the first string’s permutations is the substring of the second string.

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