Revert "Initial commit"

This reverts commit 96a896be11b94a319d07d1789bc835fbc88b748b.
Revert "Revert "Initial commit""

This reverts commit 0c967aaeac7e6ce4ecb83d992d86ccd9499aff12.
hw1

hand in hw1
hw1

....
homework 1
Merge pull request #2 from lijj47/master

13331118
Merge pull request #3 from yongbraver/master

13331071
reupload

all the copies
Merge pull request #15 from wangxuecan/master

group10