MyLeetcode/cpp_solutions/199.cpp at main · Kaminyou/MyLeetcode · GitHub

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
49
50
51
52
53
54
55
56
57
58
/**
 * 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:
    vector<int> res;
    void dfs(TreeNode* node, int level) {
        if (node == nullptr) return;
        if (res.size() == level) res.push_back(node->val);
        if (node->right) dfs(node->right, level + 1);
        if (node->left) dfs(node->left, level + 1);
    }
    vector<int> rightSideView(TreeNode* root) {
        dfs(root, 0);
        return res;
    }
};


// V2
// /**
//  * 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:
//     vector<int> rightSideView(TreeNode* root) {
//         vector<int> res;
//         queue<TreeNode*> q;
//         if (root) q.push(root);
//         while (!q.empty()) {
//             int n = q.size();
//             for (int i = 0; i < n; ++i) {
//                 TreeNode* node = q.front();
//                 q.pop();
//                 if (i == n - 1) res.push_back(node->val);
//                 if (node->left) q.push(node->left);
//                 if (node->right) q.push(node->right);
//             }
//         }
//         return res;
//     }
// };