LC#101 checks if given Binary Tree is symmetric/mirror of itself, recursive soln

Author: NirmalSilwal

Leetcode/easy/SymmetricTree101.java

@@ -0,0 +1,51 @@
+package easy;
+
+public class SymmetricTree101 {
+
+	private class TreeNode {
+		int val;
+		TreeNode left;
+		TreeNode right;
+
+		TreeNode() {
+		}
+
+		TreeNode(int val) {
+			this.val = val;
+		}
+
+		TreeNode(int val, TreeNode left, TreeNode right) {
+			this.val = val;
+			this.left = left;
+			this.right = right;
+		}
+	}
+
+	public boolean isSymmetric(TreeNode root) {
+
+		if (root.left == null && root.right == null)
+			return true;
+
+		if (root.left == null || root.right == null)
+			return false;
+
+		return isSymmetric(root.left, root.right);
+	}
+
+	private boolean isSymmetric(TreeNode node1, TreeNode node2) {
+
+		if (node1 == null && node2 == null)
+			return true;
+
+		if (node1 == null || node2 == null)
+			return false;
+
+		if (node1.val != node2.val)
+			return false;
+
+		boolean leftright = isSymmetric(node1.left, node2.right);
+		boolean rightleft = isSymmetric(node1.right, node2.left);
+
+		return leftright && rightleft;
+	}
+}