219. Contains Duplicate II[easy] Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most k. 错误解法: class Solut…

142. Linked List Cycle II[easy] 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? 解法一: /** * Definition for singl…

680. Valid Palindrome II[easy] Given a non-empty string s, you may delete at most one character. Judge whether you can make it a palindrome. Example 1: Input: "aba" Output: True Example 2: Input: "abca" Output: True Explanation: You co…

题目: Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k. 翻译: 给定一个整数数组和一个整数k.找出是否存在下标i,j使得nums[i] = nums[j].同一时候i…

Given a non-empty string s, you may delete at most one character. Judge whether you can make it a palindrome. Example 1: Input: "aba" Output: True Example 2: Input: "abca" Output: True Explanation: You could delete the character 'c'. N…

160. Intersection of Two Linked Lists[easy] 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 ↘ c1 → c2 → c3 ↗ B: b1 → b2 → b3 begin to intersect at n…

167. Two Sum II - Input array is sorted[easy] Given an array of integers that is already sorted in ascending order, find two numbers such that they add up to a specific target number. The function twoSum should return indices of the two numbers such…

217. Contains Duplicate[easy] Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct. 解法一: clas…

203. Remove Linked List Elements[easy] Remove all elements from a linked list of integers that have value val. ExampleGiven: 1 --> 2 --> 6 --> 3 --> 4 --> 5 --> 6, val = 6Return: 1 --> 2 --> 3 --> 4 --> 5 Credits:Special than…

82. Remove Duplicates from Sorted List II[Medium] Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. For example,Given 1->2->3->3->4->4->5, return 1->2->5…