思路:
根据题目的意思剪去不符合条件的子树,可以从树的叶子开始往下剪,这里用递归。
/**
* 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* pruneTree(TreeNode* root) {
if(!root) return NULL;
root->left=pruneTree(root->left);
root->right=pruneTree(root->right);
if(!root->left&&!root->right)
{
if(root->val==0) return NULL;
else return root;
}
return root;
}
};