lowest common ancestor -c++

TreesAlgorithms/lowestCommonAncestorBinaryTree/lowest_common_ancestor_binary_tree.cpp

@@ -0,0 +1,29 @@
+// https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/
+
+
+class Solution {
+public:
+    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) 
+    {
+        if(root == NULL)
+            return NULL;
+
+        if(root==p || root ==q)
+            return root;
+        TreeNode *l = lowestCommonAncestor(root->left, p, q);
+        TreeNode *r = lowestCommonAncestor(root->right, p, q);
+
+        // If both of the above calls return Non-NULL, then one key 
+        // is present in once subtree and other is present in other, 
+        // So this node is the LCA 
+        if(l && r)
+            return root;
+
+        // Otherwise check if left subtree or right subtree is LCA 
+        if(l)
+            return l;
+        else
+            return r;
+
+    }
+};