标签：style blog io color ar os sp for div
Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).
For example, this binary tree is symmetric:
1 / 2 2 / \ / 3 4 4 3
But the following is not:
1 / 2 2 \ 3 3
Note:
Bonus points if you could solve it both recursively and iteratively.
C++代码实现：
#include<iostream> #include<new> #include<vector> using namespace std; //Definition for binary tree struct TreeNode { int val; TreeNode *left; TreeNode *right; TreeNode(int x) : val(x), left(NULL), right(NULL) {} }; class Solution { public: bool isSymmetric(TreeNode *root) { if(root==NULL) return true; return isSubtree(root->left,root->right); } bool isSubtree(TreeNode *root1,TreeNode *root2) { if(root1==NULL||root2==NULL) return (root1==NULL)&&(root2==NULL); return (root1->val==root2->val)&&isSubtree(root1->left,root2->right)&&isSubtree(root1->right,root2->left); } void createTree(TreeNode *&root) { int i; cin>>i; if(i!=0) { root=new TreeNode(i); if(root==NULL) return; createTree(root->left); createTree(root->right); } } }; int main() { Solution s; TreeNode *root; s.createTree(root); cout<<s.isSymmetric(root)<<endl; }
总结：二叉树的相似、同构、镜像，3种类型。。
标签：style blog io color ar os sp for div
原文地址：http://www.cnblogs.com/wuchanming/p/4102987.html
