静水流深

Implement the following operations of a queue using stacks. push(x) -- Push element x to the back of queue.pop() -- Removes the element from in front of queue.peek() -- Get the front element.empty(

Given a non-negative integer num, repeatedly add all its digits until the result has only one digit. For example: Given num = 38, the process is like: 3 + 8 = 11, 1 + 1 = 2. Since 2 has on

Given two binary trees, write a function to check if they are equal or not. Two binary trees are considered equal if they are structurally identical and the nodes have the same value. /** * Def

Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times. You may assume that the array is non-empty and the majority element

题目： Remove all elements from a linked list of integers that have value val. Example Given: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6 Return: 1 --> 2 --> 3 --> 4 --> 5 Credits: Speci

Number of Digit One  Total Accepted: 307 Total Submissions: 1853 Given an integer n, count the total number of digit 1 appearing in all non-negative integers less than or equal to n.

Given a singly linked list, determine if it is a palindrome. Follow up: Could you do it in O(n) time and O(1) space? 没有达到上述的 O(1) space。 C++ 代码如下： Connecting to proxy server(10.109.247.19

Given an array of n integers where n > 1, nums, return an array output such that output[i] is equal to the product of all the elements of nums except nums[i]. Solve it without division and in O

Find the contiguous subarray within an array (containing at least one number) which has the largest product. For example, given the array [2,3,-2,4], the contiguous subarray [2,3] has the largest

Given a string of numbers and operators, return all possible results from computing all the different possible ways to group numbers and operators. The valid operators are+, - and *. Example 1 I

Implement atoi to convert a string to an integer. Hint: Carefully consider all possible input cases. If you want a challenge, please do not see below and ask yourself what are the possible input ca

Given two strings s and t, write a function to determine if t is an anagram of s. For example, s = "anagram", t = "nagaram", return true. s = "rat", t = "car", return false. Note: You may a

Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters for "abcabcbb" is "abc", which the length is 3. Fo

You are given two linked lists representing two non-negative numbers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a link

Given an array of integers, find two numbers such that they add up to a specific target number. The function twoSum should return indices of the two numbers such that they add up to the target, whe

Given an integer, write a function to determine if it is a power of two. Credits: Special thanks to @jianchao.li.fighter for adding this problem and creating all test cases. bool isPowerOfTwo(i

题目： Write a function to delete a node (except the tail) in a singly linked list, given only access to that node. Supposed the linked list is 1 -> 2 -> 3 -> 4 and you are given the third node

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists. 分析： 就是归并排序的merge过程，只不过用链表实现了。 可以递归进行，也可以迭代。 自己的代码又臭又