 # 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: The left subtree of a node contains only nodes with keys less than the node’s key. The right subtree of a node contains only nodes with keys greater than the node’s key. Both the left and right subtrees must also

# 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…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).

# Leet Code : Find the Duplicate Number / Element C++ ,Java , Python Solution:

Given an array of integers nums containing n + 1 integers where each integer is in the range [1, n] inclusive. There is only one repeated number in nums, return this repeated number. You must solve the problem without modifying the array nums and uses only constant extra space. Example 1: Input: nums = [1,3,4,2,2] Output: 2 Example 2: Input: nums = [3,1,3,4,2] Output: 3 Constraints: 1 <= n <= 105

# Leet Code: Rotate Array C++ Python || JavaScript || Java solution:

Given an array, rotate the array to the right by k steps, where k is non-negative. Example 1: Input: nums = [1,2,3,4,5,6,7], k = 3 Output: [5,6,7,1,2,3,4] Explanation: rotate 1 steps to the right: [7,1,2,3,4,5,6] rotate 2 steps to the right: [6,7,1,2,3,4,5] rotate 3 steps to the right: [5,6,7,1,2,3,4] Example 2: Input: nums = [-1,-100,3,99], k = 2 Output:

# Leet Code : Merge k Sorted Lists C++ , Java , Python solution

You are given an array of k linked-lists lists, each linked-list is sorted in ascending order. Merge all the linked-lists into one sorted linked-list and return it. Example 1: Input: lists = [[1,4,5],[1,3,4],[2,6]] Output: [1,1,2,3,4,4,5,6] Explanation: The linked-lists are: [ 1->4->5, 1->3->4, 2->6 ] merging them into one sorted list: 1->1->2->3->4->4->5->6 Example 2: Input: lists = [] Output: