Create 1361_Validate_Binary_Tree_Nodes.java

Author: mkhuzaima

1361_Validate_Binary_Tree_Nodes.java

@@ -0,0 +1,41 @@
+// id: 1361
+// Name: Validate Binary Tree Nodes
+// link: https://leetcode.com/problems/validate-binary-tree-nodes/
+// Difficulty: Medium
+
+class Solution {
+    public boolean validateBinaryTreeNodes(int n, int[] leftChild, int[] rightChild) {
+        boolean [] visited;
+        // for improvement, find root and apply bfs on root node only.
+        for (int root = 0; root < n; root++) {
+            visited = new boolean[n];
+            // perform traversal from this node
+            // bfs
+            Queue<Integer> q = new LinkedList<Integer>();
+            q.offer(root);
+
+            int visitedCount = 0;
+
+            boolean flag = true; // false, if cycle
+            while (!q.isEmpty()) {
+                int e = q.poll();
+                visitedCount++;
+
+                if (visited[e]) {
+                    flag = false;
+                    break;
+                }
+                
+                visited[e] = true;
+
+                if (leftChild[e] != -1)  q.offer(leftChild[e]); 
+                if (rightChild[e] != -1) q.offer(rightChild[e]);
+            }
+            // check if all are visited
+            if (flag && visitedCount == n) {
+                return true;
+            }
+        }
+        return false;
+    }
+}