diff --git a/src/offer/Question28.java b/src/offer/Question28.java new file mode 100644 index 0000000..f6461b2 --- /dev/null +++ b/src/offer/Question28.java @@ -0,0 +1,34 @@ +package offer; + +import leecode.tree.TreeNode; + +import java.util.ArrayList; +import java.util.List; +import java.util.Objects; +import java.util.Stack; + +/** + * 对称的二叉树 + */ +public class Question28 { + public boolean isSymmetry(TreeNode node) { + TreeNode lHead = new TreeNode(0); + lHead.left = node; + TreeNode rHead = new TreeNode(0); + rHead.left = node; + return dfs(lHead.left, rHead.left); + } + + private boolean dfs(TreeNode lHead, TreeNode rHead) { + if (lHead == null && rHead == null) { + return true; + } + if (lHead == null || rHead == null) { + return false; + } + if (!Objects.equals(lHead.val, rHead.val)) { + return false; + } + return dfs(lHead.left, rHead.right) && dfs(lHead.right, rHead.left); + } +}