Yahoo

4 problems asked at Yahoo.

Easy (2)

Two Sum (Leetcode 1)

Two Pointers, Arrays

Valid Parentheses (Leetcode 20)

Stack, Strings

Medium (2)

Group Anagrams (Leetcode 49)

Arrays, Strings, Sorting...

Longest Substring Without Repeating Characters (leetcode 3)

Sliding Window, Strings, Hashing