摘要：Given a List of words, return the words that can be typed using letters of alphabet on only one row's of American keyboard like the image below. Examp 阅读全文

摘要：Given a positive integer, output its complement number. The complement strategy is to flip the bits of its binary representation. Note: Example 1: Exa 阅读全文

摘要：Given an array of 2n integers, your task is to group these integers into n pairs of integer, say (a1, b1), (a2, b2), ..., (an, bn) which makes sum of 阅读全文

摘要：Given two binary trees and imagine that when you put one of them to cover the other, some nodes of the two trees are overlapped while the others are n 阅读全文

摘要：The Hamming distance between two integers is the number of positions at which the corresponding bits are different. Given two integers x and y, calcul 阅读全文

摘要：Initially, there is a Robot at position (0, 0). Given a sequence of its moves, judge if this robot makes a circle, which means it moves back to the or 阅读全文