diff --git a/1038-231204-pass/main.cpp b/1038-231204-pass/main.cpp
new file mode 100644
index 0000000..b1de922
--- /dev/null
+++ b/1038-231204-pass/main.cpp
@@ -0,0 +1,125 @@
+#include<stdcpp.h>
+using namespace std;
+
+struct TreeNode {
+    int val;
+    TreeNode *left;
+    TreeNode *right;
+    TreeNode() : val(0), left(nullptr), right(nullptr) {}
+    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
+    TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
+};
+
+class Solution {
+public:
+    priority_queue<int, vector<int>, greater<int> > vals;
+    int cnt = 0;
+    void traverse(TreeNode * node){
+        vals.push(node->val);
+        cnt++;
+        if(node->left!=nullptr)  traverse(node->left);
+        if(node->right!=nullptr)  traverse(node->right);
+    }
+    TreeNode* bstToGst(TreeNode* root) {
+        traverse(root);
+        int val[110];
+        int idx[110];
+        int pref[110],sum=0;
+        for(int i = 0 ; i < cnt ; i++){
+            val[i] = vals.top();
+            vals.pop();
+            if(i==0)
+                pref[i] = val[i];
+            else{
+                pref[i] = pref[i-1] + val[i];
+            }
+        }
+        sum = pref[cnt-1];
+        for(int i = 0 ; i < cnt ; i++){
+            idx[val[i]] = sum - pref[i];
+        }
+        stack<TreeNode*> sta;
+        sta.push(root);
+        while(sta.empty() == false){
+            TreeNode* top_node = sta.top();
+            cout<<"top_node is "<<top_node->val<<endl;
+            sta.pop();
+            if(top_node->left!=nullptr) sta.push(top_node->left);
+            if(top_node->right!=nullptr) sta.push(top_node->right);
+            top_node->val+=idx[top_node->val];
+        }
+        cnt = 0;
+        std::priority_queue<int, std::vector<int>, std::greater<int>> empty;
+        vals.swap(empty);
+        return root;
+    }
+};
+
+void create(int * val, int cnt, TreeNode *cur,int idx){
+    int left_idx = (idx + 1) * 2 - 1;
+    int right_idx = (idx + 1) * 2 ;
+    if(left_idx > cnt){
+        cur->left = nullptr;
+        cur->right = nullptr;
+        return;
+    }
+    if(right_idx > cnt){
+        cur->right = nullptr;
+        return;
+    }
+    if(val[left_idx] == -1){
+        cur -> left = nullptr;
+    }else{
+        TreeNode * left_child = new TreeNode(val[left_idx]);
+        cur->left = left_child;
+        create(val,cnt,left_child,left_idx);
+    }
+    if(val[right_idx] == -1){
+        cur -> right = nullptr;
+    }else{
+        TreeNode * right_child = new TreeNode(val[right_idx]);
+        cur->right = right_child;
+        create(val, cnt, right_child, right_idx);
+    }
+    return;
+}
+void traverse(TreeNode* node){
+    cout<<node->val<<' ';
+    if(node->left != nullptr){
+        traverse(node->left);
+    }
+    if(node->right != nullptr){
+        traverse(node->right);
+    }
+    return;
+}
+TreeNode* createTree(int * val, int cnt){
+    TreeNode * root = new TreeNode(val[0]);
+    cout<<"create a tree"<<endl;
+    create(val,cnt,root, 0);
+    traverse(root);
+    cout<<"\ndone"<<endl;
+    // cout<<endl;
+    return root;
+}
+int main(){
+    Solution sol;
+
+    //create example 1
+    const int ex1_length = 15;
+    int ex1_data[ex1_length] = {4,1,6,0,2,5,7,-1,-1,-1,3,-1,-1,-1,8};
+    TreeNode * ex1 = createTree(ex1_data, ex1_length);
+    sol.bstToGst(ex1);
+    traverse(ex1);
+    cout<<endl;
+
+    const int ex2_length = 3;
+    int ex2_data[ex2_length] = {0,-1,1};
+    TreeNode * ex2 = createTree(ex2_data,ex2_length);
+    sol.bstToGst(ex2);
+    traverse(ex2);
+    cout<<endl;
+
+
+    return 0;
+}
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