diff --git a/sample.cpp b/sample.cpp
new file mode 100644
index 0000000..30cda6a
--- /dev/null
+++ b/sample.cpp
@@ -0,0 +1,103 @@
+#include<iostream>
+#include<vector>
+#include<set>
+#include<algorithm>
+using namespace std;
+
+class Solution{
+    public:
+    struct Point{
+        int x;
+        int y;
+        bool operator<(const Point& other) const{
+            if (x!=other.x)return x<other.x;
+            return y < other.y;
+        }
+    };
+
+    static bool cmp(const Point &a, const Point &b){
+        return a.x < b.x ||(a.x == b.x && a.y < b.y);
+    }
+    static bool cmp1(const Point &a, const Point &b){
+        return a.y < b.y ||(a.y == b.y && a.x < b.x);
+    }
+    void print_vec(set<Point> x){
+        for(auto e: x){
+            cout<<'('<<e.x<<','<<e.y<<"), ";
+        }
+        cout<<endl;
+    }
+    int numIdleDrives(vector<int> x, vector<int> y){
+
+        vector<Point> poi;
+        set<Point> hor;
+        set<Point> ver;
+
+        int n = x.size();
+        for(int i = 0 ; i < n ; i++){
+            poi.push_back({x[i], y[i]});
+        }
+        sort(poi.begin(), poi.end(), cmp);
+        int cur_x = poi[0].x;
+        int sum_x = 0;
+        Point last_point = poi[0];
+        hor.insert(last_point);
+        // horizontal
+        for(int i = 1 ; i < n ; i++){
+            Point cur_p = poi[i];
+            if(cur_p.x == cur_x){
+                sum_x += 1;
+            }
+            else{
+                if(sum_x >= 2)
+                    hor.insert(last_point);
+                hor.insert(cur_p);
+                sum_x = 1;
+                cur_x = cur_p.x;
+            }
+            last_point = cur_p;
+        }
+        //vertical
+        sort(poi.begin(), poi.end(), cmp1);
+        int cur_y = poi[0].y;
+        int sum_y = 1;
+        last_point = poi[0];
+        ver.insert(last_point);
+        for(int i = 1 ; i < n ; i++){
+            Point cur_p = poi[i];
+            if(cur_p.y == cur_y){
+                sum_y += 1;
+            }
+            else{
+                if(sum_y >= 2)
+                    ver.insert(last_point);
+                ver.insert(cur_p);
+                sum_y = 1;
+                cur_y = cur_p.y;
+            }
+            last_point = cur_p;
+        }
+        set<Point> rlt;
+        for(const auto& point : ver){
+            rlt.insert(point);
+        }
+        for(const auto& point : hor){
+            rlt.insert(point);
+        }
+         
+        return n - rlt.size();
+    }
+};
+int main(){
+    Solution *sol = new Solution();
+    vector<int>x = {0, 0, 0, 0, 0, 1, 1, 1, 2, -1, -1, -2, -1};
+    vector<int>y = {-1, 0, 1, 2, -2, 0, 1, -1, 0, 1, -1, 0, 0};
+    cout<<sol->numIdleDrives(x,y)<<endl;
+    vector<int>x1 = {1, 1, 1, 2, 2, 2, 2, 3, 3, 3};
+    vector<int>y1 = {1, 2, 3, 1, 2, 3, 5, 1, 2, 3};
+    cout<<sol->numIdleDrives(x1,y1)<<endl;
+    vector<int>x2 = {0, -1,0,0,3,5,4,4,4};
+    vector<int>y2 = {0,0,1,-1,0,0,1,-1,0};
+    cout<<sol->numIdleDrives(x2,y2)<<endl;
+}
+// {0,1},{0,4},{1,0},{2,2},{1,3},{0,4},{2,5},{3,4}
\ No newline at end of file