Create main.cpp

Author: JawadSher

17 - Binary Tree Data Structure Problems/26 - Lowest Common Ancestor of a Binary Tree/main.cpp

@@ -0,0 +1,25 @@
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
+        if(root == NULL) return NULL;
+
+        if(root -> val == p -> val || root -> val == q -> val) return root;
+
+        TreeNode* leftAns = lowestCommonAncestor(root -> left, p, q);
+        TreeNode* rightAns = lowestCommonAncestor(root -> right, p, q);
+
+        if(leftAns != NULL && rightAns != NULL) return root;
+        else if(leftAns != NULL && rightAns == NULL) return leftAns;
+        else if(leftAns == NULL && rightAns != NULL) return rightAns;
+        else return NULL;
+    }
+};