# leetcode problems

## Leet code 799. Champagne Tower (Medium)

Leetcode 799. Champagne Tower: Hey there, coding enthusiasts! Welcome back to another exciting coding session. Today’s problem is a treat—literally! We’re going to solve the “Champagne Tower” problem. Problem Explanation : In summary, LeetCode 799 Champagne Tower is a coding problem that involves pouring champagne into a tower of glasses and calculating how much champagne a […]

## Leet Code : Trapping Rain Water Solution Java | CPP | JS

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining. Input: height = [0,1,0,2,1,0,1,3,2,1,2,1] Output: 6 Explanation: The above elevation map (black section) is represented by array [0,1,0,2,1,0,1,3,2,1,2,1]. In this case, 6 units of rain water (blue section) are being trapped. CPP solution

## Leet Code : Validate Binary Search Tree Java | CPP | Python solution

Given the root of a binary tree, determine if it is a valid binary search tree (BST). A valid BST is defined as follows: Input: root = [2,1,3] Output: true Solution : Java DFS : Python : CPP : Inorder solution :

## Leet Code : Maximum Score from Performing Multiplication Operations Cpp | Java | Python solution

Two integer arrays, nums and multipliers, of sizes n and m, respectively, are provided to you, where n >= m. The arrays are all one-dimensional. You start with a score of zero. You need to carry out precisely m operations. On the ith (1-indexed) action, you will: Choose one integer x from the beginning or

## LeetCode 15 : Three (3) Sum

LeetCode 15. Pattern: Hey there, coding enthusiasts! Welcome back to another exciting coding session. Today’s problem is a treat—literally! We’re going to solve the “three sum” or “LeetCode .15” Approaches Two-Pointer Approach: 1. Sorting the Array 2. Initialization 3. Handling Edge Case 4. Main Loop Over Array 5. Duplicate Check 6. Two-Pointer Approach 7. Finding

## Leet Code : Longest Palindromic Substring Java | CPP | Java Script | Python Solution

Given a string s, return the longest palindromic substring in s. A string is called a palindrome string if the reverse of that string is the same as the original string. Example 1: Input: s = “babad” Output: “bab” Explanation: “aba” is also a valid answer. Example 2: Input: s = “cbbd” Output: “bb” Solution : JavaScript : CPP

## Leet Code: Longest Substring Without Repeating Characters Java | JavaScript | CPP | Python Solution

Find the length of the longest substring without repeated characters given a string s. Example 1: Input: s = “abcabcbb” Output: 3 Explanation: The answer is “abc”, with the length of 3. Example 2: Input: s = “bbbbb” Output: 1 Explanation: The answer is “b”, with the length of 1. Example 3: Input: s =

## Leet Code : Add Two List – Java | CPP | Javascript | Python

You are given two non-empty linked lists that each represent a non-negative integer. The digits are kept in reverse order, with each node containing only one digit. Add the two numbers together and return the total as a linked list. Except for the number 0 itself, you may presume that the two numbers do not

## Leet Code : Median of two sorted array -CPP || java || Python || Java Script

Provide the median of the two sorted arrays given two sorted arrays of sizes m and n, respectively. The entire complexity of the run time should be O(log (m+n)). Eg 1: Numbers1 = [1,3], Numbers2 = [2] Result: 2.00000 Explanation: the merged array equals [1,2,3], and the median is 2. Eg 2: Numbers1 = [1,2],

## leet code 1. Two sum (easy)

Leet Code 1. Two Sum : Hey there, coding enthusiasts! Welcome back to another exciting coding session. Today’s problem is a treat—literally! We’re going to solve the “two sum ” or “Leet Code .1‘ Time Complexity: C++: 1. Brute Force Approach: LeetCode 15 : Three (3) Sum Notice: This approach has a time complexity of

## Binary Tree Level Order Traversal

Given the root of a binary tree, return the level order traversal of its nodes’ values. (i.e., from left to right, level by level). Example 1: Input: root = [3,9,20,null,null,15,7] Output: [[3],[9,20],[15,7]] Example 2: Input: root = [1] Output: [[1]] Example 3:

## Leet Code :Linked List Cycle II Java || Python || C++ solution

Given the head of a linked list, return the node where the cycle begins. If there is no cycle, return null. There is a cycle in a linked list if there is some node in the list that can be reached again by continuously following the next pointer. Internally, pos is used to denote the index of the node that tail’s next pointer is connected

## leet Code : Validate Binary Search Tree Java || C++ || C || pYthon

Given the root of a binary tree, determine if it is a valid binary search tree (BST). A valid BST is defined as follows: Example 1: Input: root = [2,1,3] Output: true Solution

## Leet Code :Running Sum of 1d Array Solution C++ || Python || Java

Given an array nums. We define a running sum of an array as runningSum[i] = sum(nums[0]…nums[i]). Return the running sum of nums. Example 1: Input: nums = [1,2,3,4] Output: [1,3,6,10] Explanation: Running sum is obtained as follows: [1, 1+2, 1+2+3, 1+2+3+4]. Example 2: Input: nums = [1,1,1,1,1] Output: [1,2,3,4,5] Explanation: Running sum is obtained as follows: [1, 1+1,

## TCS and Infosys Database , SQL questions | TCS and Infosys Technical Round Question

What is the difference between inner and outer join? Explain with example. Inner Join Inner join is the most common type of Join which is used to combine the rows from two tables and create a result set containing only such records that are present in both the tables based on the joining condition (predicate).