Create smallest-subtree-with-all-the-deepest-nodes.cpp

Author: kamyu104

C++/smallest-subtree-with-all-the-deepest-nodes.cpp

@@ -0,0 +1,39 @@
+// Time:  O(n)
+// Space: O(h)
+
+/**
+ * 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* subtreeWithAllDeepest(TreeNode* root) {
+        return dfs(root).node;
+    }
+
+private:
+    struct Result {
+        TreeNode *node;
+        int depth;
+    };
+
+    Result dfs(TreeNode *node) {
+        if (!node) {
+            return {nullptr, 0};
+        }
+        auto left = dfs(node->left);
+        auto right = dfs(node->right);
+        if (left.depth > right.depth) {
+            return {left.node, left.depth + 1};
+        }
+        if (left.depth < right.depth) {
+            return {right.node, right.depth + 1};
+        }
+        return {node, left.depth + 1};
+    }
+};