Easy
- unique-email-addresses
- two-sum
- count-and-say
- binary-tree-level-order-traversal-ii
- symmetric-tree
- balanced-binary-tree
- valid-palindrome
- pascals-triangle
- third-maximum-number
- convert-a-number-to-hexadecimal
- find-pivot-index
- best-time-to-buy-and-sell-stock
Medium
- fruit-into-baskets
- number-of-islands
- clone-graph
- word-ladder
- course-schedule
- lru-cache
- permutations
- permutations-ii
- string-to-integer
- powx-n
- valid-sudoku
- divide-two-integers
- decode-ways
- max-area-of-island
- reverse-words-in-a-string
- valid-parenthesis-string
- validate-ip-address
- set-matrix-zeroes
- sort-colors
- maximum-subarray
- next-permutation