Day 3, #100, #101, Same Tree, Symmetric Tree

Same Tree

bool isSameTree(TreeNode *p, TreeNode *q) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (p == NULL && q == NULL) return true;
        if (p == NULL || q == NULL) return false;
        if (p->val != q->val) return false;
        return isSameTree(p->left,q->left) && isSameTree(p->right,q->right);
}

Symmetric Tree
Solution #1

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class Solution {
public:
    
    bool isSymmetricRec(TreeNode *p,TreeNode *q) {
        if (p == NULL && q == NULL) return true;
        if (p == NULL || q == NULL) return false;
        if (p->val != q->val) return false;
        return isSymmetricRec(p->left, q->right) && isSymmetricRec(p->right, q->left);
    }

    bool isSymmetric(TreeNode *root) {
        // Start typing your C/C++ solution below
        // DO NOT write int main() function
        if (root == NULL) return true;
        return isSymmetricRec(root->right,root->left);
        
    }
};