题解 | #递归——合并二叉树#

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 * };
 */
//先序遍历可以构建第三棵树
//递归方式构建每一个节点
class Solution {
public:
    /**
     * 
     * @param t1 TreeNode类 
     * @param t2 TreeNode类 
     * @return TreeNode类
     */
    TreeNode* mergeTrees(TreeNode* t1, TreeNode* t2) {
        // write code here
        if(t1 == NULL) return t2;
        if(t2 == NULL) return t1;
        TreeNode *root = new TreeNode(t1->val + t2->val); //新节点
        root->left = mergeTrees(t1->left, t2->left); 
        root->right = mergeTrees(t1->right, t2->right);
        return root;
    }
};