0%

LeetCode 623. Add One Row to Tree

Posted on Edited on In

题目

原题在此

解析

常规的level order traversal即可, 没什么难度.

代码

c++

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    TreeNode* addOneRow(TreeNode* root, int v, int d) {
        if(!root) return root;
        // if(d == 1) return make_shared<TreeNode>(v, root, NULL);
        if(d == 1) {
            TreeNode * foo = new TreeNode(v, root, NULL);
            return foo;
        }
        queue<TreeNode*> q;
        q.push(root);
        while(!q.empty() && d) {
            if(!--d) return root;
            int n = q.size();
            for(int i = 0; i < n; ++i) {
                TreeNode* tmp = q.front();
                q.pop();
                if(d == 1) {
                    TreeNode* l = tmp->left;
                    TreeNode* r = tmp->right;
                    tmp->left = new TreeNode(v);
                    tmp->right = new TreeNode(v);
                    tmp->left->left = l;
                    tmp->right->right = r;
                } else {
                    if(tmp -> left) q.push(tmp -> left);
                    if(tmp -> right) q.push(tmp -> right);
                }
            }
        }
        return root;
    } 
};