2-sum Problem: Given an array of integers nums[] and an integer target, return indices of the two numbers such that their sum is equal to the target. Note: Assume that there is **exactly one solution*, and you are not allowed to use the same* element twice. Example: If target is equal to 6 and num[1] = 3, then nums[1] + nums[1] = target is not a solution.
Longest Consecutive Sequence in an Array: You are given an array of ‘N’ integers. You need to find the length of the longest sequence which contains the consecutive elements.
Find K-th Permutation Sequence: Given N and K, where N is the sequence of numbers from 1 to N([1,2,3….. N]) find the Kth permutation sequence. For N = 3 the 3! Permutation sequences in order would look like this
Serialize And Deserialize a Binary Tree: Design an algorithm to serialize and deserialize a binary tree. There is no restriction on how your serialization/deserialization algorithm should work. You just need to ensure that a binary tree can be serialized to a string and this string can be deserialized to the original tree structure.