solutions for interview questions at leedcode.com

1. Two Sum
   1) O(N^2)
   2) O(N) with extra space
2. Median of Two Sorted Arrays
3. Length of Longest Substring
   1) O(N) with map
4. Add Two Numbers
5. Longest Palindromic Substring
6. ZigZag Conversion
7. LRUCache
8. Work Break
9. Multiply Strings
10. LargestRectangleInHistogram
11. Tree From Pre and InOrder
12. Divide two integers
13. Search in Rotated Sorted Array
14. Max points on a line
15. Climbing Stairs
16. Search Range
17. Buy and Sell Stock
28. Spiral Matrix II
29. Sum Root To Leaf Numbers
30. Set Matrix Zeros
31. Word Break II