题解 | #二叉树的镜像#

//c++使用栈辅助
/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
#include <cstddef>
#include <stack>
class Solution {
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param pRoot TreeNode类 
     * @return TreeNode类
     */
    TreeNode* Mirror(TreeNode* pRoot) {
        // write code here
        if (pRoot==NULL) {
            return NULL;
        }
        stack<TreeNode*> s;
        s.push(pRoot);
        while (!s.empty()) {
            TreeNode* node=s.top();
            s.pop();
            if (node->left) s.push(node->left);
            if(node->right) s.push(node->right);
            TreeNode* temp=node->left;
            node->left=node->right;
            node->right=temp;
        }
        return pRoot;
    }
};