Given an array nums of n integers, are there elements a, b, c in nums such that a + b + c = 0? Find all unique triplets in the array which gives the sum of zero. Note: The solution set must not contain duplicate triplets. Example: Given array nums = [-1, 0, 1, 2, -1, -4], A solution set is: [ [-1, 0, 1], [-1, -1, 2] ] Solution 1:…… Continue reading Leetcode 15 3 Sum
Tag: Leetcode
Leetcode 5 Longest Palindromic Substring Java Solution
Given a string s, find the longest palindromic substring 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 1: class Solution { public String longestPalindrome(String s) { if(s==null || s.length()<=1) return s; boolean dp[][] =…… Continue reading Leetcode 5 Longest Palindromic Substring Java Solution
Leetcode 4 Median of Two Sorted Arrays Java Solution
There are two sorted arrays nums1 and nums2 of size m and n respectively. Find the median of the two sorted arrays. The overall run time complexity should be O(log (m+n)). You may assume nums1 and nums2 cannot be both empty. Example 1: nums1 = [1, 3] nums2 = [2] The median is 2.0 Example 2: nums1 = [1, 2] nums2 = [3,…… Continue reading Leetcode 4 Median of Two Sorted Arrays Java Solution
Leetcode 3 Longest Substring Without Repeating Characters
Given a string, find the length of the longest substring without repeating characters. Example 1: Input: “abcabcbb” Output: 3 Explanation: The answer is “abc”, with the length of 3. Example 2: Input: “bbbbb” Output: 1 Explanation: The answer is “b”, with the length of 1. Example 3: Input: “pwwkew” Output: 3 Explanation: The answer is “wke”, with…… Continue reading Leetcode 3 Longest Substring Without Repeating Characters
Leetcode 2 Add Two Numbers Java Solution
You are given two non-empty linked lists representing two non-negative integers. 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 linked list. You may assume the two numbers do not contain any leading zero, except the number 0 itself. Example: Input: (2 ->…… Continue reading Leetcode 2 Add Two Numbers Java Solution
Leetcode 1 Two Sum Java Solution
Given an array of integers, return indices of the two numbers such that they add up to a specific target. You may assume that each input would have exactly one solution, and you may not use the same element twice. Example: Given nums = [2, 7, 11, 15], target = 9, Because nums[0] + nums[1] = 2 + 7 = 9,…… Continue reading Leetcode 1 Two Sum Java Solution
Leetcode 406 Queue Reconstruction by Height
Suppose you have a random list of people standing in a queue. Each person is described by a pair of integers (h, k), where h is the height of the person and k is the number of people in front of this person who have a height greater than or equal to h. Write an algorithm to reconstruct the queue. Note:The…… Continue reading Leetcode 406 Queue Reconstruction by Height
Leetcode 200 Number of Islands (Java) With Video Explanation
Given a 2d grid map of ‘1’s (land) and ‘0’s (water), count the number of islands. An island is surrounded by water and is formed by connecting adjacent lands horizontally or vertically. You may assume all four edges of the grid are all surrounded by water. Example : Input: 11000 11000 00100 00011 Output: 3 Solution: We…… Continue reading Leetcode 200 Number of Islands (Java) With Video Explanation
Leetcode 56 Merge Intervals (Java)
Given a collection of intervals, merge all overlapping intervals. Example 1: Input: [[1,3],[2,6],[8,10],[15,18]] Output: [[1,6],[8,10],[15,18]] Explanation: Since intervals [1,3] and [2,6] overlaps, merge them into [1,6]. Solution: We can solve this by comparing the start of the next interval with the end of the current interval and merged if the start of the next interval…… Continue reading Leetcode 56 Merge Intervals (Java)
Leetcode 23: Merge K Sorted Lists (Java)
Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. Example: Input: [ 1->4->5, 1->3->4, 2->6 ] Output: 1->1->2->3->4->4->5->6 Solution: For this problem, the brute force solution would be passing all the lists and perform Merge Sort, but for the optimal solution we will use minHeap using…… Continue reading Leetcode 23: Merge K Sorted Lists (Java)