Swap Nodes in Pairs and Reverse Nodes in K Groups

Let’s continue… Problem Statement: Swap Nodes in Pairs Given a linked list, swap every two adjacent nodes and return its head. Example: Given 1->2->3->4, you should return the list as 2->1->4->3. Note: Your algorithm should use only constant extra space. You may not modify the values in the list's nodes, only nodes itself may be changed.… Continue reading Swap Nodes in Pairs and Reverse Nodes in K Groups

Remove Nth Node from End of List and Generate Parentheses

Let’s continue… Problem Statement: Remove Nth Node from End of List Given a linked list, remove the n-th node from the end of list and return its head. Example: Given linked list: 1->2->3->4->5, and n = 2. After removing the second node from the end, the linked list becomes 1->2->3->5. Note: Given n will always… Continue reading Remove Nth Node from End of List and Generate Parentheses

Container with Most Water and Longest Common Prefix

Problem Statement: Given n non-negative integers a1, a2, ..., an , where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together with x-axis forms a container, such that the container contains the… Continue reading Container with Most Water and Longest Common Prefix

Regular_Expression _Matching

Let me continue.... Problem Statement: Given an input string (s) and a pattern (p), implement regular expression matching with support for '.' and '*'. '.' Matches any single character. '*' Matches zero or more of the preceding element. The matching should cover the entire input string (not partial). Note: s could be empty and contains only… Continue reading Regular_Expression _Matching

Longest_Palindromic_ Sub_String

OK, Let's continue.... Problem Statement: Given a string s, find the longest palindromic sub string in s. You may assume that the maximum length of s is 1000. Example 1: Input: "babad" Output: "bab" Note: "aba" is also a valid answer. Example 2: Input: "cbbd" Output: "bb" Solution One: Brute Force Simple but not efficient.… Continue reading Longest_Palindromic_ Sub_String

Longest_Sub_String_ No_Repeat_Characters

Let me continue my work here. Longest substring without Repeating Characters Problem Statement: Given a string, find the length of the longest sub string without repeating characters. Example 1: Input: "abcabcbb" Output: 3 Explanation: The answer is "abc", which the length is 3. Example 2: Input: "bbbbb" Output: 1 Explanation: The answer is "b", with the length… Continue reading Longest_Sub_String_ No_Repeat_Characters