一：解题思路
Time:O(n),Space:O(n)
二：完整代码示例 (C++版和Java版)
C++:
class Solution { public: TreeNode* mergeTrees(TreeNode* t1, TreeNode* t2) { if (t1 == NULL && t2 == NULL) return NULL; if ((t1 == NULL) && (t2 != NULL)) return t2; if ((t1 != NULL) && (t2 == NULL)) return t1; t1->val = (t1->val+t2->val); t1->left = mergeTrees(t1->left,t2->left); t1->right = mergeTrees(t1->right,t2->right); return t1; } };
Java:
class Solution { public TreeNode mergeTrees(TreeNode t1, TreeNode t2) { if((t1==null)&&(t2==null)) return null; if((t1==null)&&(t2!=null)) return t2; if((t1!=null)&&(t2==null)) return t1; t1.val=t1.val+t2.val; t1.left=mergeTrees(t1.left,t2.left); t1.right=mergeTrees(t1.right,t2.right); return t1; } }
原文：https://www.cnblogs.com/repinkply/p/12512341.html