Skip to content

leet code

994 - Populating Next Right Pointers in Each Node

문제에서는 추가적인 공간을 사용하지 말라고 했는데,

그것까지는 고려하지 못 해서 아쉽습니다.

 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
45
46
47
48
/*
// Definition for a Node.
class Node {
public:
    int val;
    Node* left;
    Node* right;
    Node* next;

    Node() : val(0), left(NULL), right(NULL), next(NULL) {}

    Node(int _val) : val(_val), left(NULL), right(NULL), next(NULL) {}

    Node(int _val, Node* _left, Node* _right, Node* _next)
        : val(_val), left(_left), right(_right), next(_next) {}
};
*/
#include<queue>

class Solution {
public:
    Node* connect(Node* root) {
        if(!root) return nullptr;
     queue<Node*> q;
        q.push(root);

        while(!q.empty())
        {
            int len_q = q.size();
            for(int i=0; i<len_q; ++i)
            {
                Node* cur = q.front();
                q.pop();
                if(i+1<len_q){
                    cur->next = q.front();
                }else{
                    cur->next = nullptr;
                }
                if(cur->left)
                    q.push(cur->left);
                if(cur->right)
                    q.push(cur->right);
            }
        }

        return root;
    }
};