Create 1609-even-odd-tree.java

Author: sujal-goswami

java/1609-even-odd-tree.java

@@ -0,0 +1,36 @@
+/*_____________________________
+  Time Complexity: O(n)
+  Space Complexity: O(n)
+_______________________________*/
+
+class Solution {
+    public boolean isEvenOddTree(TreeNode root) {
+        Queue<TreeNode> q = new LinkedList<>();
+        q.add(root);
+        boolean evenLevel = true;
+
+        while(!q.isEmpty()){
+            int prev = (evenLevel)? Integer.MIN_VALUE: Integer.MAX_VALUE;
+            int sz = q.size();
+
+            for(int i = 0; i < sz; i++){
+                TreeNode curr = q.poll();
+                int nodeVal = curr.val;
+
+                if((evenLevel && nodeVal % 2 == 0) || (!evenLevel && nodeVal % 2 != 0))
+                    return false;
+                if((evenLevel && nodeVal <= prev) || (!evenLevel && nodeVal >= prev))
+                    return false;
+
+                prev = nodeVal;    
+
+                if(curr.left != null)
+                    q.add(curr.left);
+                if(curr.right != null)
+                    q.add(curr.right);        
+            }
+            evenLevel = !evenLevel;
+        }
+        return true;
+    }
+}