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