摘要：
Write an algorithm to determine if a number is "happy". A happy number is a number defined by the following process: Starting with any positive intege 阅读全文
摘要：
We define a harmonious array is an array where the difference between its maximum value and its minimum value is exactly 1. Now, given an integer arra 阅读全文
摘要：
Given two non-empty binary trees s and t, check whether tree t has exactly the same structure and node values with a subtree of s. A subtree of s is a 阅读全文