Best Time to Buy and Sell Stock III 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 complete at most two transactions. Note: You may not engage in multiple […]
Reverse Linked List II Reverse a linked list from position m to n. Do it in-place and in one-pass. For example: Given 1->2->3->4->5->NULL, m = 2 and n = 4, return 1->4->3->2->5->NULL. Note: Given m, n satisfy the following condition: 1 ≤ m ≤ n ≤ length of list. tag: […]
Binary Tree Inorder Traversal Given a binary tree, return the inorder traversal of its nodes’ values. For example: Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [1,3,2]. Note: Recursive solution is trivial, could you do it iteratively? confused what “{1,#,2,3}” means? > read more on how binary tree […]
Valid Palindrome Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases. For example, “A man, a plan, a canal: Panama” is a palindrome. “race a car” is not a palindrome. Note: Have you consider that the string might be empty? This is a […]
Copy List with Random Pointer A linked list is given such that each node contains an additional random pointer which could point to any node in the list or null. Return a deep copy of the list. tag: hashtable, linked-list 虽然被标记为hard，但代码不长。 问题关键是，在拷贝完next指针后，要根据原来链表中的random的地址，找到新建的链表中对应的node的地址，这里我们用一个hashtable来实现，在拷贝next指针时，将对应关系记录下来。 空间复杂度o(n)，时间复杂度o(n)。 /** * Definition for singly-linked list with […]
Divide Two Integers Divide two integers without using multiplication, division and mod operator. If it is overflow, return MAX_INT. tags: math, binary search 8/10/2015 update Reference http://yucoding.blogspot.com/2013/01/leetcode-question-28-divide-two-integers.html class Solution { public: int divide(int dividend, int divisor) { int flag = 1; long ldividend = dividend; long ldivisor = divisor; if(ldividend […]
Remove Element Given an array and a value, remove all instances of that value in place and return the new length. The order of elements can be changed. It doesn’t matter what you leave beyond the new length. 简单题，与上一题Remove Element in Sorted Array类似 class Solution { public: int removeElement(int A[], […]
