Apple

1 Unique Paths Medium 2 Distinct Subsequences Hard 3 Gas Station Medium 4 Non-overlapping Intervals Medium 5 Happy Number Easy 6 Counting Bits Easy 7 Two Sum Easy 8 Valid Palindrome Easy 9 Longest Repeating Character Replacement Medium 10 Generate Parentheses Medium 11 Find Minimum in Rotated Sorted Array Medium 12 Remove Nth Node From End of List Medium 13 Reverse Nodes in k-Group Hard 14 Lowest Common Ancestor of a Binary Search Tree Medium 15 Binary Tree Maximum Path Sum Hard 16 K Closest Points to Origin Medium 17 Permutations Medium 18 Number of Islands Medium 19 Course Schedule Medium 20 Min Cost to Connect All Points Medium 21 House Robber Medium 22 Word Break Medium 23 Target Sum Medium 24 Maximum Subarray Medium 25 Valid Parenthesis String Medium 26 Rotate Image Medium 27 Detect Squares Medium 28 Reverse Integer Medium 29 Valid Sudoku Medium 30 Trapping Rain Water Hard