Description
Submission
/** * 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: TreeNode* mergeTrees(TreeNode* t1, TreeNode* t2) { if(t1 == NULL && t2 == NULL) return NULL; if(t1 == NULL) return t2; if(t2 == NULL) return t1; t1->val += t2->val; t1->left = mergeTrees(t1->left, t2->left); t1->right = mergeTrees(t1->right, t2->right); return t1; } };