Given an array of positive integers, find the number of triplets and pairs that are

divisible by $3.$

$($ People who used brute force here were not shortlisted. Hashing based solution

was working $)$

Find the lowest common ancestor in Binary Search Tree for given two nodes.

Given two numbers n and m $,$ find the closest number near to n which is divisible

by m $.$ If more than $1$ number is possible, print the highest number. Your Algorithm

should be of $O(1)$ time complexity, $O(n)$ will land you in TLE $($Time Limit

Exceeded $)$give answer for these three qns pls