Create 1361-validate-binary-tree-nodes.js

Author: aadil42

javascript/1361-validate-binary-tree-nodes.js

@@ -0,0 +1,43 @@
+/**
+ * DFS
+ * Time O(n) | Space O(n)
+ * https://leetcode.com/problems/validate-binary-tree-nodes/
+ * 
+ * @param {number} n
+ * @param {number[]} leftChild
+ * @param {number[]} rightChild
+ * @return {boolean}
+ */
+var validateBinaryTreeNodes = function(n, leftChild, rightChild) {
+    
+    const visited = new Set();
+
+    const findRoot = () => {
+      
+      const childrenSet = new Set();
+      for(let i = 0; i < n; i++) {
+        childrenSet.add(i);
+      }
+      
+      for(let i = 0; i < n; i++) {
+        childrenSet.delete(leftChild[i]);
+        childrenSet.delete(rightChild[i]);
+      }
+
+      return [...childrenSet][0];
+    }
+
+    const dfs = (i) => {
+
+      if(i === -1) return true;
+      if(visited.has(i)) return false;
+
+      const left = leftChild[i];
+      const right = rightChild[i];
+      visited.add(i);
+      return dfs(left) && dfs(right);
+    }
+
+    const root = findRoot();
+    return dfs(root) && visited.size === n;
+};