quiteThe third homework had...
The 14 exercises were broken up into 10 groups...
| Rosen1.7 2, 10acf, 16b | Rosen1.7 8cd + B from handout #5 |
|||||
| Rosen1.8 2 | Rosen1.8 8ab, 20ab | B from handout #6 | ||||
| Rosen2.1 34 | Rosen2.2 2 | Rosen2.2 6b | Rosen2.2 18 | |||
| Rosen1.8 28a |
...and the assignment's 71 points were (unevenly) divided among the 10 groups as follows:
| 8 | 5 | |||||
| 6 | 8 | 8 | ||||
| 12 | 12 | 4 | 6 | |||
| 2* |
You should be able to find the corresponding ten scores on the front
page of your homework, arranged in a three-row quite
Your total score (out of 71) should also appear prominently on the front page.
A few comments on specific exercises...
| Rosen1.8 2, 8ab, 20ab. |
The symbol "&1" means that you neglected to prove some result that you were supposed to prove. | ||
|---|---|---|---|
| Rosen2.2 6b. |
Please note that the bit string 1010 requires only 2 bitwise ANDs, not 4... 1010 Likewise, a billion-bit string consisting of 2 1's and 999999998 0's will still only require 2 bitwise ANDs (!). These two examples show that you can't just say, "n bitwise ANDs are required to find the number of 1 bits in a string S"; you need to include a crucial qualification: namely, the phrase, "in the worst case." [If you used n in your answer without explaining what it stood for, we assumed that you meant "the length of S."] The comment "why?" means that you didn't justify your answer. In general, exercises like this require proofs. |
Our solutions for the third homework have been posted.
For those who are curious, the median score was 51, and the mean score was 48.8 (sigma ~ 13).