摘要：
Write a SQL query to find all duplicate emails in a table namedPerson.+----+---------+| Id | Email |+----+---------+| 1 | a@b.com || 2 | c@d.com |... 阅读全文
摘要：
Given an integer, write a function to determine if it is a power of two.判断一个integer是否为2的幂。 1 public class Solution { 2 public static boolean isPow... 阅读全文
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 integer... 阅读全文
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Given two binary trees, write a function to check if they are equal or not.Two binary trees are considered equal if they are structurally identical an... 阅读全文
摘要：
Write a function that takes an unsigned integer and returns the number of ’1' bits it has (also known as theHamming weight).For example, the 32-bit in... 阅读全文