剑指Offer，对称的二叉树

zebinh · zebinh · commit 6089af1b50c4 · 2020-01-13T23:05:01.000+08:00
diff --git a/swordoffer/SymmetricalSolution.java b/swordoffer/SymmetricalSolution.java
@@ -0,0 +1,42 @@
+/**
+ * 剑指Offer，对称的二叉树
+ */
+
+
+class TreeNode {
+    int val = 0;
+    TreeNode left = null;
+    TreeNode right = null;
+
+    public TreeNode(int val) {
+        this.val = val;
+
+    }
+
+}
+
+public class SymmetricalSolution {
+    boolean isSymmetrical(TreeNode pRoot)
+    {
+        if (pRoot == null) {
+            return true;
+        }
+        return symmetrical(pRoot.left, pRoot.right);
+    }
+
+    public boolean symmetrical(TreeNode aTree, TreeNode bTree) {
+        if (aTree == null && bTree == null) {
+            return true;
+        }
+        
+        if ( (aTree != null && bTree == null) || (aTree == null && bTree != null) ) {
+            return false;
+        }
+
+        if (aTree.val != bTree.val) {
+            return false;
+        }
+
+        return symmetrical(aTree.left, bTree.right) && symmetrical(aTree.right, bTree.left);
+    }
+}
