Samsung

4 problems asked at Samsung.

Easy (2)

Two Sum (Leetcode 1)

Two Pointers, Arrays

Valid Parentheses (Leetcode 20)

Stack, Strings

Medium (1)

Longest Substring Without Repeating Characters (leetcode 3)

Sliding Window, Strings, Hashing

Hard (1)

Trapping Rain Water (LC 42)

Two Pointers, Prefix and Suffix Arrays, Stack