2.7 done

Author: camilosalazar98

Python/chapter02/2.7 - Intersection/camilo_soultion_2.7.py

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+"""
+Intersection: Given two (singly) linked lists, determine if the two lists
+intersect. Return the inter­secting node. Note that the intersection is defined
+based on reference, not value.That is, if the kth node of the first linked list
+is the exact same node (by reference) as the jth node of the second linked list,
+then they are intersecting.
+Hints:#20, #45, #55, #65, #76, #93, #111, #120, #129
+
+
+Had a really hard time with this question:
+https://www.youtube.com/watch?v=gMeDsyEXnbM
+
+"""
+
+
+
+class Node:
+    #Singly link list
+    def __init__(self,data = None):
+        self.data = data
+        self.next = None
+
+class linklist:
+    #linkList class
+    def __init__(self):
+        self.head = None
+        self.size = 0
+
+    def getSize(self):
+        return self.size
+
+    def push(self,data):
+        node = Node(data)# create a new node
+
+        if self.head == None: #check to see if the head node is empty
+            self.head = node # If its empty add it to the new node
+            self.size = 1
+            return
+        #if the head of the linklist is filled
+
+        current = self.head
+        while current.next is not None:#Check the current postion is empty
+        #Move to the next line if nothing is there
+            current = current.next
+
+
+        current.next = node #point self.head to a new node
+        self.size+=1
+
+    def lenght(self):
+        #note the count doesn't start at zero
+        cur = self.head
+        counter = 0
+        while cur is not None:
+            counter+=1
+            cur = cur.next
+        print('Linklist len: '+str(counter))
+        return counter
+
+    def printList(self):
+        curr = self.head
+        elem = []
+
+        while(curr != None):
+            elem.append(curr.data)
+            curr = curr.next
+        print(elem)
+    #1->2->3
+    def remove_node(self,data):
+        #1->2->3
+        curr = self.head
+        if curr is not None and curr.data == data:
+            self.head = curr.next
+            curr = None
+        #look for the node that has the data we are looking for
+        while curr is not None:
+            if curr.data == data:
+                break
+            prev = curr
+            curr = curr.next
+
+        #if data isn't found just reutrn
+        if(curr == None):
+            return
+
+        #allow us to unlink the nodes
+        prev.next = curr.next
+        curr = None
+
+    """
+    def make_next(self,llist,num):
+        curr_llist = llist.head
+        curr = self.head
+
+        size_ = self.size - llist.size
+        print(size_)
+        size = 0
+        if self.size == llist.size:
+            while curr and curr_llist is not None:
+                if curr.data == num:
+                    curr_llist.next = curr
+
+                curr = curr.next
+                curr_llist = curr_llist.next
+
+        while curr is not None:
+            if size != size_:
+                size += 1
+                curr = curr.next
+            while curr and curr_llist is not None:
+                if curr.data == num:
+                    curr_llist.next = curr
+
+                curr = curr.next
+                curr_llist = curr_llist.next
+
+        self.head = list_A.head
+        head_A = list_A.head
+        while head_A.next:
+            head_A = head_A.next
+        head_A.next = list_B.head
+
+    def CombineLlist(self,list_A,list_B):
+        list_B = list_B.head
+        head_A = self.head
+        while head_A is not None:
+            head_A = head_A.next
+        head_A.next = list_B.head
+"""
+
+
+def intersection(listA,ListB):
+    headA = listA.head
+    headB = ListB.head
+
+    if not headA or not headB:
+        return None
+
+    a = headA
+    b = headB
+
+
+    while a != b and a!= None and b != None:
+        if not a:
+            a = headB
+        else:
+
+            a = a.next
+
+        if not b:
+            b = headA
+        else:
+
+            b = b.next
+    return a.data
+
+
+
+
+
+
+# 1->2->3->4->5->6->7
+# 3->5->6->7
+llist_1 = linklist()
+llist_2 = linklist()
+llist_1.push(1)
+llist_1.push(3)
+llist_1.push(5)
+llist_1.push(7)
+llist_1.push(9)
+llist_1.push(11)
+
+llist_2.push(2)
+llist_2.push(4)
+llist_2.push(9)
+llist_2.push(11)
+
+print(intersection(llist_1,llist_2))