http://web.cps.msu.edu/~cps830/sampleprob2.html
1. 9.1 2. 9.4 3. 9.7 4. 9.11** May be tricky. You must consider the stack size of recursive call if you use recursion. 5. 9.17 6. 9.19 7. 9.21 (worthwhile to implement the algoritm) 8. 9.23 9. 9.36 10. 9.40 11. 9.41 12. 9.43 13. 9.49 14. 9.50 15. 9.53 (a)* 16. 9.54* 17. 9.56