https://classroom.github.com/a/i-tW_O3h
1. Heap 완성
- insert, delete, show(level-order traversal)
- insert number that represent some priority
2. BST 완성
- insert, delete, show(in order traversal)
3. Sets 완성 + EqualSets()
- insert pair(n,m)
- findset(n) : return all the member of set
- equalSet(n, m): compare equal condition of two sets that containing n and m, respectively
4. Programming projects
- Leftist Trees
1) insert some x with priority
2) in-order traversal
3) level-order traversal