摘要：
二分法相关 153. Find Minimum in Rotated Sorted Array Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might 阅读全文
摘要：
字典树（Trie树相关） 208. Implement Trie (Prefix Tree) Implement a trie with insert, search, and startsWith methods. （Medium） Note:You may assume that all inp 阅读全文
摘要：
数学题 172. Factorial Trailing Zeroes Given an integer n, return the number of trailing zeroes in n!. Note: Your solution should be in logarithmic time c 阅读全文
摘要：
位运算相关 三道题 231. Power of Two 位运算相关 三道题 231. Power of Two Given an integer, write a function to determine if it is a power of two. （Easy） 分析： 数字相关题有的可以考 阅读全文
摘要：
Implement the following operations of a stack using queues. （Easy） push(x) -- Push element x onto stack. pop() -- Removes the element on top of the st 阅读全文
摘要：
Evaluate the value of an arithmetic expression in Reverse Polish Notation. （Medium） Valid operators are +, -, *, /. Each operand may be an integer or 阅读全文
摘要：
Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. （Easy） For example,"A man, a plan, a can 阅读全文
摘要：
Given an unsorted array of integers, find the length of the longest consecutive elements sequence. （Hard） For example,Given [100, 4, 200, 1, 3, 2],The 阅读全文
摘要：
Given a binary tree, find the maximum path sum. （Hard） For this problem, a path is defined as any sequence of nodes from some starting node to any nod 阅读全文
摘要：
Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may comple 阅读全文