摘要： Given two words (beginWord and endWord), and a dictionary's word list, find all shortest transformation sequence(s) from beginWord to endWord, such th 阅读全文

摘要： Design a stack that supports push, pop, top, and retrieving the minimum element in constant time. push(x) -- Push element x onto stack. pop() -- Remov 阅读全文

摘要： We are given two strings, A and B. A shift on A consists of taking string A and moving the leftmost character to the rightmost position. For example, 阅读全文

摘要： Design and implement a data structure for Least Frequently Used (LFU) cache. It should support the following operations: get and put. get(key) - Get t 阅读全文

摘要： Given a binary tree, find its maximum depth. The maximum depth is the number of nodes along the longest path from the root node down to the farthest l 阅读全文

摘要： Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary). You may assume that the intervals were initia 阅读全文

摘要： Write a program to find the node at which the intersection of two singly linked lists begins. For example, the following two linked lists: begin to in 阅读全文

摘要： Implement int sqrt(int x). Compute and return the square root of x, where x is guaranteed to be a non-negative integer. Since the return type is an in 阅读全文

摘要： Given a list of sorted characters letters containing only lowercase letters, and given a target letter target, find the smallest element in the list t 阅读全文

摘要： There are n bulbs that are initially off. You first turn on all the bulbs. Then, you turn off every second bulb. On the third round, you toggle every 阅读全文