Problems

1. 1. Print all possible letter combination in a phone number: http://stackoverflow.com/questions/2344496/how-can-i-print-out-all-possible-letter-combinations-a-given-phone-number-can-re

2. Finding 3 elements whose sum is closest to the input number : http://stackoverflow.com/questions/2070359/finding-three-elements-in-an-array-whose-sum-is-closest-to-an-given-number

3. Arrangement of blocks : http://stackoverflow.com/questions/7692653/google-interview-arrangement-of-blocks

4. Dynamic Programming : http://stackoverflow.com/questions/6135443/dynamic-programming-question