Polish stack solution.

This commit is contained in:
Donne Martin
2016-02-20 08:11:49 -05:00
parent 08fabdf58d
commit 7a166bed67
2 changed files with 23 additions and 29 deletions

View File

@@ -137,9 +137,9 @@
"%%writefile stack.py\n",
"class Node(object):\n",
"\n",
" def __init__(self, data):\n",
" def __init__(self, data, next=None):\n",
" self.data = data\n",
" self.next = None\n",
" self.next = next\n",
"\n",
"\n",
"class Stack(object):\n",
@@ -148,21 +148,18 @@
" self.top = top\n",
"\n",
" def push(self, data):\n",
" node = Node(data)\n",
" node.next = self.top\n",
" node = Node(data, self.top)\n",
" self.top = node\n",
"\n",
" def pop(self):\n",
" if self.top is not None:\n",
" data = self.top.data\n",
" self.top = self.top.next\n",
" return data\n",
" return None\n",
" if self.top is None:\n",
" return None\n",
" data = self.top.data\n",
" self.top = self.top.next\n",
" return data\n",
"\n",
" def peek(self):\n",
" if self.top is not None:\n",
" return self.top.data\n",
" return None\n",
" return self.top.data if self.top is not None else None\n",
"\n",
" def is_empty(self):\n",
" return self.peek() is None"
@@ -308,21 +305,21 @@
],
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