Same Tree

/**
 * Definition for binary tree
 * struct TreeNode {
 *     int val;
 *     struct TreeNode *left;
 *     struct TreeNode *right;
 * };
 */
bool isSameTree(struct TreeNode *p, struct TreeNode *q) {
    if(!p && !q) return true;
    if(!p || !q) return false;
    if(p->val != q->val) return false;
    return isSameTree(p->left,q->left)&&isSameTree(p->right,q->right);
}