class Solution {
public:
    void inorder(TreeNode* root, int low, int high, int& res){
        if(root != nullptr){
            inorder(root->left, low, high, res);
            if(root->val <= high && root->val >= low){
                res += root->val;
            }
            inorder(root->right, low, high, res);
        }
    }
    int rangeSumBST(TreeNode* root, int low, int high) {
        int res=0;
        inorder(root, low, high, res);
        return res;
    }
};

java 语：

class Solution {
    int res;
    public void inorder(TreeNode root, int low, int high){
        if(root != null){
            inorder(root.left, low, high);
            if(root.val <= high && root.val >= low){
                res += root.val;
            }
            inorder(root.right, low, high);
        }
    }
    public int rangeSumBST(TreeNode root, int low, int high) {
        res = 0;
        inorder(root, low, high);
        return res;
    }
}

leetcode问题938。问题是找到bst[低，高]的范围和
我在这两种语言中做的都差不多（我猜，但我对java是新手），但是java代码与cpp相比怎么那么快呢？它与指针和引用或者站点使用的编译器有关吗？
当做