Practice-Leetcode/TreeSymmetry.cpp at master · adilhamid/Practice-Leetcode · 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
59
60
61
62
63
64
65
66
/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:

 bool isSymmetric(TreeNode* root) {

        if(!root) return true;

        queue<TreeNode*> queue;

        queue.push(root->left);
        queue.push(root->right);

        while(!queue.empty()){
            if(queue.size() % 2 != 0 ) return false;

            TreeNode* topLeft = queue.front();
            queue.pop();
            TreeNode* topRight = queue.front();
            queue.pop();

            if(!topLeft && !topRight)
                continue;

            if(!topLeft || !topRight)
                return false;

            if(topLeft->val != topRight->val) return false;


            queue.push(topLeft->left);
            queue.push(topRight->right);
            queue.push(topLeft->right);
            queue.push(topRight->left);


        }
        return true;

    }

    bool isSymmetricREC(TreeNode* root) {
        return !root || isSymm(root->left, root->right);
    }

    bool isSymm(TreeNode* left, TreeNode* right){
        if(!left && !right)
            return true;

        if(!left || !right)
            return false;

        return left->val == right->val && ( isSymm(left->left, right->right) && isSymm(left->right, right->left));

    }


};