Given a positive integer n, find the smallest integer which can be formed by rearranging the digits of n and is greater than n. If no such integer exists, return -1.
Given two strings s1 and s2, return true if s2 contains any permutation of s1 as a substring, otherwise return false. In other words, check if one of the permutations of s1 exists as a substring within s2.
Given an integer array, find the shortest continuous subarray such that, if you sort this subarray in non-decreasing order, the whole array will become sorted.
Given an array of integers, return the number of triplets that can form a valid triangle. A valid triangle is formed when the sum of any two sides is greater than the third side.
