Create solution.cpp

Author: aishsingh

IntersectionOfTwoLinkedLists/solution.cpp

@@ -0,0 +1,48 @@
+/**
+ * Definition for singly-linked list.
+ * struct ListNode {
+ *     int val;
+ *     ListNode *next;
+ *     ListNode(int x) : val(x), next(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) 
+    {
+        auto curNodeA = headA;
+        auto curNodeB = headB;
+
+        // Map the number of times each node is visited
+        unordered_map<ListNode*, int> nodeVisitCount;
+
+        while (curNodeA != nullptr || curNodeB != nullptr)
+        {
+            // Add nodes to map to keep track of visited nodes
+            // And also check for intersected nodes
+
+            if (curNodeA != nullptr)
+            {
+                if (++nodeVisitCount[curNodeA] > 1)
+                    return curNodeA;
+            }
+
+            if (curNodeB != nullptr)
+            {
+                if (++nodeVisitCount[curNodeB] > 1)
+                    return curNodeB;
+            }
+
+            // iterate to next nodes to continue search
+
+            if (curNodeA != nullptr)
+                curNodeA = curNodeA->next;
+
+            if (curNodeB != nullptr)
+                curNodeB = curNodeB->next;
+        }
+
+        // if we reached here then no intersection node was found
+        return nullptr; 
+    }
+};