Amazon Interview Questions for Programmer Analyst

Given an array, for each element, find the index of the next greater element. If no greater element is present, return -1. For example, if arr = [72,73,74,70,69,70,75,76,73,72], the expected output is [1, 1, 4, 3, 1, 1, 1, -1, -1, -1].

Given an array of integers nums and an integer target, return indices of the two numbers such that they add up to target. You may assume that each input would have exactly one solution, and you may not use the same element twice.

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 be binary search trees.

Given the head of a linked list, remove the n-th node from the end of the list and return its head.

Given the root of a binary tree, check whether it is a mirror of itself (i.e., symmetric around its center).