ChuanjieZhu

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list.Example 1:Input: 1->2->3->3->4->4->5Output: 1-&gt...

Given a sorted linked list, delete all duplicates such that each element appear only once.Example 1:Input: 1->1->2Output: 1->2Example 2:Input: 1->1->2->3->3Output: 1-...

Write a program to find the node at which the intersection of two singly linked lists begins.For example, the following two linked lists:A: a1 → a2 ↘ ...

Reverse a linked list from position m to n. Do it in one-pass.Note: 1 ≤ m ≤ n ≤ length of list.Example:Input: 1->2->3->4->5->NULL, m = 2, n = 4Output: 1->4->3->2->5-...

Reverse a singly linked list.Example:Input: 1->2->3->4->5->NULLOutput: 5->4->3->2->1->NULLFollow up:A linked list can be reversed either iteratively or recursi...

Given a linked list, return the node where the cycle begins. If there is no cycle, return null.Note: Do not modify the linked list.Follow up:Can you solve it without using extra space?判断链表知否存在环...

Given a linked list, determine if it has a cycle in it.Follow up:Can you solve it without using extra space?给你一个链表，让你在原地判断这个链表有没有环。 思路：使用快慢指针法。遍历，如果没有环，快指针最终指向NULL，也就是结尾，如果有环，慢指针最终会追上快指针。...

Given an array of non-negative integers, you are initially positioned at the first index of the array.Each element in the array represents your maximum jump length at that position.Determine if you ar...

Given an integer array with all positive numbers and no duplicates, find the number of possible combinations that add up to a positive integer target.Example:nums = [1, 2, 3]target = 4The possible ...

Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers.Note:All numbers will be p...

Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sums to target.Each number in candidates may o...

The set [1,2,3,...,n] contains a total of n! unique permutations.By listing and labeling all of the permutations in order, we get the following sequence for n = 3:"123""132""213""231""312""321"Giv

Given a collection of numbers that might contain duplicates, return all possible unique permutations.Example:Input: [1,1,2]Output:[ [1,1,2], [1,2,1], [2,1,1]]这一题和上一题类似，就是数组里有重复的元素。思路：递归+深度优先搜...

Given a collection of distinct integers, return all possible permutations.Example:Input: [1,2,3]Output:[ [1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], [3,2,1]]求全排列。思路：递归+深度优先搜索因为排列要使用所有数...

Given a set of candidate numbers (candidates) (without duplicates) and a target number (target), find all unique combinations in candidates where the candidate numbers sums to target.The same repeated...

Given two integers n and k, return all possible combinations of k numbers out of 1 ... n.Example:Input: n = 4, k = 2Output:[ [2,4], [3,4], [2,3], [1,2], [1,3], [1,4],]求组合数。思路：递归+深度优先搜索（...

Given a 32-bit signed integer, reverse digits of an integer.Example 1:Input: 123Output: 321Example 2:Input: -123Output: -321Example 3:Input: 120Output: 21Note:Assume we are dealing with an envir...

Implement a basic calculator to evaluate a simple expression string.The expression string contains only non-negative integers, +, -, *, / operators and empty spaces . The integer division should trunc...

Implement a basic calculator to evaluate a simple expression string.The expression string may contain open ( and closing parentheses ), the plus + or minus sign -, non-negative integers and empty spac...

Given two binary strings, return their sum (also a binary string).The input strings are both non-empty and contains only characters 1 or 0.Example 1:Input: a = "11", b = "1"Output: "100"Example 2:Inp...

Given an integer, write a function to determine if it is a power of two.Example 1:Input: 1Output: trueExample 2:Input: 16Output: trueExample 3:Input: 218Output: false判断一个数是不是2的次幂。思路：主要是利用2的整数幂的二进制只...

Given an array containing n distinct numbers taken from 0, 1, 2, ..., n, find the one that is missing from the array.Example 1:Input: [3,0,1]Output: 2Example 2:Input: [9,6,4,2,3,5,7,0,1]Output: 8N...

A peak element is an element that is greater than its neighbors.Given an input array nums, where nums[i] ≠ nums[i+1], find a peak element and return its index.The array may contain multiple peaks, in ...

Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.You may assume no duplicates in the array.Exam...

Given an array of integers nums sorted in ascending order, find the starting and ending position of a given target value.Your algorithm's runtime complexity must be in the order of O(log n).If the tar...

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:Integers in each row are sorted in ascending from left to right.Integers in each col...

Write an efficient algorithm that searches for a value in an m x n matrix. This matrix has the following properties:Integers in each row are sorted from left to right.The first integer of each row is ...

Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.Example 1:Input: 121Output: trueExample 2:Input: -121Output: falseExplanation: F...

Given a 2D binary matrix filled with 0's and 1's, find the largest rectangle containing only 1's and return its area.Example:Input:[ ["1","0","1","0","0"], ["1","0","1",&a

Given n non-negative integers representing the histogram's bar height where the width of each bar is 1, find the area of largest rectangle in the histogram.Above is a histogram where width of each bar...

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.(i.e.,  [0,1,2,4,5,6,7] might become  [4,5,6,7,0,1,2]).Find the minimum element.The array may contain dupl...

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.(i.e.,  [0,1,2,4,5,6,7] might become  [4,5,6,7,0,1,2]).Find the minimum element.You may assume no duplicat...

Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three integers. You may assume that each input would have exactly...

Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero.Note:Elements in a triplet (a,b,c) must be in...

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, where i...

Given two sorted integer arrays A and B, merge B into A as one sorted array.Note: You may assume that A has enough space to hold additional elements from B. The number of elements initialized in A and...