intersection of nodes

Author: nickolasteixeira

Python/chapter02/2.7 - Intersection/Nick.py

@@ -0,0 +1,131 @@
+#!/usr/bin/python3
+
+import unittest
+
+
+class Node:
+    def __init__(self, data, next=None):
+        self.data = data
+        self.next = next
+
+
+class SinglyLinkedList:
+    def __init__(self):
+        self.head = None
+
+    def appendNode(self, data, next=None):
+        node = Node(data, next)
+        if not self.head:
+            self.head = node
+        else:
+            temp = self.head
+            while temp.next:
+                temp = temp.next
+            temp.next = node
+        print('Node added to LL-->', data)
+
+    def printMemoryValues(self):
+        temp = self.head
+        while temp:
+            print('Memory address values: ', hex(id(temp)), ' Values: ', temp.data)
+            temp = temp.next
+
+    def findNode(self, value):
+        if not self.head:
+            print('No list to iterate')
+            return
+
+        temp = self.head
+        while temp:
+            if temp.data == value:
+                return temp
+            temp = temp.next
+        return None
+
+    def findLongest(self, l1, l2):
+        if not self.head:
+            print('No list to iterate')
+            return None
+        
+        l1count, l2count = 0, 0
+        temp1, temp2 = l1.head, l2.head
+        while temp1:
+            l1count += 1
+            temp1 = temp1.next
+        
+        while temp2:
+            l2count += 1
+            temp2 = temp2.next
+        
+        if l1count > l2count:
+            longest, shortest = l1, l2
+        else:
+            longest, shortest = l2, l1
+        return abs(l1count - l2count), longest, shortest
+
+
+    def intersection(self, l1, l2):
+        if not l1.head or not l2.head:
+            print('No list to iterate -> intersection')
+            return None
+       
+        diff, longest, shortest = self.findLongest(l1, l2)
+        temp = longest.head
+        for x in range(diff):
+            temp = temp.next
+
+        temp2 = shortest.head
+        while temp:
+            if temp == temp2:
+                return temp
+            temp = temp.next
+            temp2 = temp2.next
+            
+        return None
+        
+        
+class Test(unittest.TestCase):
+    @classmethod
+    def setUpClass(cls):
+        cls.l = SinglyLinkedList()
+        cls.l.appendNode(3)
+        cls.l.appendNode(1)
+        cls.l.appendNode(5)
+        cls.l.appendNode(9)
+        cls.l.appendNode(7)
+        cls.l.appendNode(2)
+        cls.l.appendNode(1)
+        cls.l.printMemoryValues()
+
+        cls.k = SinglyLinkedList()
+        cls.k.appendNode(4)
+        node = cls.l.findNode(7)
+        cls.k.appendNode(6, node)
+        cls.k.printMemoryValues()
+
+
+        cls.p = SinglyLinkedList()
+        cls.p.appendNode(1)
+        cls.p.appendNode(2)
+        cls.p.appendNode(5)
+        cls.p.appendNode(1000)
+        cls.p.appendNode(-22)
+        cls.p.printMemoryValues()
+    @classmethod
+    def tearDownClass(cls):
+        pass
+
+
+    def printStatement(self, interNode):
+        if interNode:
+            print('Nodes intersect at address', hex(id(interNode)), ' Value: ',interNode.data)
+        else:
+            print('Nodes do not intersect')
+    def test1(self):
+        interNode = self.l.intersection(self.l, self.k)
+        interNode2 = self.l.intersection(self.l, self.p)
+        self.printStatement(interNode)
+        self.printStatement(interNode2)
+
+if __name__ == '__main__':
+    unittest.main()