SAP

4 problems asked at SAP.

Easy (3)

Implement Queue using Stacks (LeetCode 232)

Stack, Queue

Two Sum (Leetcode 1)

Two Pointers, Arrays

Valid Parentheses (Leetcode 20)

Stack, Strings

Hard (1)

Trapping Rain Water (LC 42)

Two Pointers, Prefix and Suffix Arrays, Stack