| Jeremy Hylton | 8b6323d | 2000-02-04 00:28:21 +0000 | [diff] [blame] | 1 | class Set: |
| 2 | def __init__(self): |
| 3 | self.elts = {} |
| Jeremy Hylton | 95b8614 | 2000-02-10 20:54:27 +0000 | [diff] [blame] | 4 | def __len__(self): |
| 5 | return len(self.elts) |
| Jeremy Hylton | 8b6323d | 2000-02-04 00:28:21 +0000 | [diff] [blame] | 6 | def add(self, elt): |
| 7 | self.elts[elt] = elt |
| 8 | def items(self): |
| 9 | return self.elts.keys() |
| 10 | def has_elt(self, elt): |
| 11 | return self.elts.has_key(elt) |
| Jeremy Hylton | 69926ea | 2000-02-10 00:43:22 +0000 | [diff] [blame] | 12 | def remove(self, elt): |
| 13 | del self.elts[elt] |
| Jeremy Hylton | 8b6323d | 2000-02-04 00:28:21 +0000 | [diff] [blame] | 14 | |
| 15 | class Stack: |
| 16 | def __init__(self): |
| 17 | self.stack = [] |
| 18 | self.pop = self.stack.pop |
| Jeremy Hylton | 95b8614 | 2000-02-10 20:54:27 +0000 | [diff] [blame] | 19 | def __len__(self): |
| 20 | return len(self.stack) |
| Jeremy Hylton | 8b6323d | 2000-02-04 00:28:21 +0000 | [diff] [blame] | 21 | def push(self, elt): |
| 22 | self.stack.append(elt) |
| 23 | def top(self): |
| 24 | return self.stack[-1] |