题目描述

操作给定的二叉树，将其变换为源二叉树的镜像。

输入描述

/*
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};*/
class Solution {
public:
    void Mirror(TreeNode *pRoot) {
        if(pRoot==nullptr)
            return;
        TreeNode* tmp=pRoot->left;
        pRoot->left=pRoot->right;
        pRoot->right=tmp;
        if(pRoot->left)
            Mirror(pRoot->left);
        if(pRoot->right)
            Mirror(pRoot->right);
        return;
    }
};

运行时间：8ms
占用内存：592k

/*
struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};*/
class Solution {
public:
    void Mirror(TreeNode *pRoot) {
        if(pRoot==nullptr)
            return;
        stack<TreeNode*> st;
        st.push(pRoot);
        while(!st.empty()){
            TreeNode* root=st.top();st.pop();
            if(root->left || root->right){
                TreeNode* tmp=root->left;
                root->left=root->right;
                root->right=tmp;
            }
            if(root->left)
                st.push(root->left);
            if(root->right)
                st.push(root->right);
        }
        return;
    }
};