摘要：
思路一：递归 思路二：迭代 从头至尾，依次反转相邻节点指针 阅读全文
摘要：
121. Best Time to Buy and Sell Stock Say you have an array for which the ith element is the price of a given stock on day i. If you were only permitte 阅读全文
摘要：
122. Best Time to Buy and Sell Stock II Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to 阅读全文
摘要：
167. Two Sum II - Input array is sorted Given an array of integers that is already sorted in ascending order, find two numbers such that they add up t 阅读全文
摘要：
思路：罗马计数转阿拉伯数字。罗马数字的构造：XCVIII表示98，DCXXI表示621。从右至左，用max记录当前最大数的符号，若当前索引处的数字比max大，则将总数加上当前索引字符所代表的的数，如果小，则将总数减去当前索引所代表的数字。 阿拉伯数字转换为罗马计数 思路：罗马数字的基本型为：I = 阅读全文
摘要：
A binary watch has 4 LEDs on the top which represent the hours (0-11), and the 6 LEDs on the bottom represent the minutes (0-59). Each LED represents 阅读全文
摘要：
217. Contains Duplicate Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears a 阅读全文
摘要：
350. Intersection of Two Arrays II Given two arrays, write a function to compute their intersection. Example: Given nums1 = [1, 2, 2, 1], nums2 = [2, 阅读全文
摘要：
409. Longest Palindrome Given a string which consists of lowercase or uppercase letters, find the length of the longest palindromes that can be built 阅读全文
摘要：
169. Majority Element Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times. Y 阅读全文