| 1 | # Fixed division |
| 2 | |
| 3 | class SingleArrayStacks(object): |
| 4 | |
| 5 | def __init__(self, stacksize = 100, number = 3): |
| 6 | self.stacksize = stacksize |
| 7 | self.number = number |
| 8 | self.array = [None] * self.stacksize * self.number |
| 9 | self.pointer = [-1] * self.number |
| 10 | |
| 11 | def push(self, stacknum, value): |
| 12 | if self.pointer[stacknum] + 1 >= self.stacksize: |
| 13 | print "Out of space" |
| 14 | else: |
| 15 | self.pointer[stacknum] += 1 |
| 16 | self.array[self.stacktop(stacknum)] = value |
| 17 | |
| 18 | def pop(self, stacknum): |
| 19 | if self.pointer[stacknum] < 0: |
| 20 | return "Trying to pop an empty stack." |
| 21 | else: |
| 22 | data = self.array[self.stacktop(stacknum)] |
| 23 | self.array[self.stacktop(stacknum)] = None |
| 24 | self.pointer[stacknum] -= 1 |
| 25 | return data |
| 26 | |
| 27 | def peek(self, stacknum): |
| 28 | if self.pointer[stacknum] < 0: |
| 29 | print "Empty stack" |
| 30 | else: |
| 31 | return self.array[self.stacktop(stacknum)] |
| 32 | |
| 33 | def isEmpty(self, stacknum): |
| 34 | return self.pointer[stacknum] == -1 |
| 35 | |
| 36 | def stacktop(self, stacknum): |
| 37 | return self.stacksize * stacknum + self.pointer[stacknum] |
| 38 | |
| 39 | |
| 40 | |