diff --git a/leetcode/39.combination_sum/39.CombinationSum_henrytien.cpp b/leetcode/39.combination_sum/39.CombinationSum_henrytien.cpp
new file mode 100644
index 0000000..170994d
--- /dev/null
+++ b/leetcode/39.combination_sum/39.CombinationSum_henrytien.cpp
@@ -0,0 +1,100 @@
+// Source : https://leetcode.com/problems/combination-sum/
+// Author : henrytien
+// Date   : 2022-02-17
+
+/*****************************************************************************************************
+ *
+ * Given an array of distinct integers candidates and a target integer target, return a list of all
+ * unique combinations of candidates where the chosen numbers sum to target. You may return the
+ * combinations in any order.
+ *
+ * The same number may be chosen from candidates an unlimited number of times. Two combinations are
+ * unique if the frequency of at least one of the chosen numbers is different.
+ *
+ * It is guaranteed that the number of unique combinations that sum up to target is less than 150
+ * combinations for the given input.
+ *
+ * Example 1:
+ *
+ * Input: candidates = [2,3,6,7], target = 7
+ * Output: [[2,2,3],[7]]
+ * Explanation:
+ * 2 and 3 are candidates, and 2 + 2 + 3 = 7. Note that 2 can be used multiple times.
+ * 7 is a candidate, and 7 = 7.
+ * These are the only two combinations.
+ *
+ * Example 2:
+ *
+ * Input: candidates = [2,3,5], target = 8
+ * Output: [[2,2,2,2],[2,3,3],[3,5]]
+ *
+ * Example 3:
+ *
+ * Input: candidates = [2], target = 1
+ * Output: []
+ *
+ * Constraints:
+ *
+ * 	1 <= candidates.length <= 30
+ * 	1 <= candidates[i] <= 200
+ * 	All elements of candidates are distinct.
+ * 	1 <= target <= 500
+ ******************************************************************************************************/
+
+#include "../inc/ac.h"
+
+// Let N be the number of candidates, T be the target value, and M be the minimal value among the candidates.
+// Time Complexity: O(N^T/M)
+// Space Complexity: O(T/M)
+class Solution
+{
+public:
+    vector<vector<int>> combinationSum(vector<int> &candidates, int target)
+    {
+        vector<vector<int>> res;
+        vector<int> cur_res;
+        backtrack(candidates,0,target,cur_res,res);
+        return res;
+    }
+
+private:
+    void backtrack(const vector<int> &canditates, int index, int remain,
+                   vector<int> &cur_res, vector<vector<int>> &res)
+    {
+        if (remain == 0)
+        {
+            res.push_back(cur_res);
+            return;
+        }else if(remain < 0) {
+            // exceed the scope, stop exploration.
+            return;
+        }
+
+        for (int i = index; i < canditates.size(); i++)
+        {
+            if (remain >= canditates[i])
+            {
+                // Add the number into the combination
+                cur_res.push_back(canditates[i]);
+                backtrack(canditates, i, remain - canditates[i], cur_res, res);
+                // backtrack, remove the number from the combination
+                cur_res.pop_back();
+            }
+        }
+        return;
+    }
+};
+
+int main()
+{
+
+    vector<int> candidates{2, 3, 6, 7};
+    int target = 7;
+    vector<vector<int>> res = Solution().combinationSum(candidates, target);
+    for (auto &&iter : res)
+    {
+        print_vec(iter);
+    }
+
+    return 0;
+}
\ No newline at end of file
diff --git a/leetcode/39.combination_sum/README.md b/leetcode/39.combination_sum/README.md
index 6735558..5ceaa82 100644
--- a/leetcode/39.combination_sum/README.md
+++ b/leetcode/39.combination_sum/README.md
@@ -1,5 +1 @@
 # [39. Combination Sum](https://leetcode.com/problems/combination-sum/)
-
-
-
-https://leetcode-cn.com/problems/combination-sum/solution/hui-su-suan-fa-jian-zhi-python-dai-ma-java-dai-m-2/
\ No newline at end of file
diff --git a/leetcode/inc/ac.h b/leetcode/inc/ac.h
index 8748836..1991c07 100644
--- a/leetcode/inc/ac.h
+++ b/leetcode/inc/ac.h
@@ -55,4 +55,9 @@ void print(ListNode *node){
         node = node->next;
     }
 }
+void print_vec(const vector<int>& vec){
+    for(auto &&iter: vec)
+        cout << iter << " ";
+    cout << endl;
+}
 #endif /* ac_h */
diff --git a/scripts/comments_cpp.sh b/scripts/comments_cpp.sh
index 4e39dac..bf3c75a 100755
--- a/scripts/comments_cpp.sh
+++ b/scripts/comments_cpp.sh
@@ -115,7 +115,7 @@ else
 
     if [ ! -f ${source_file} ]; then
         echo "Create a new file - ${source_file}."
-        echo "\n" > ${source_file}
+        echo "" > ${source_file}
         current_time=`date +%Y-%m-%d`
     else
         if [[ "$platform" == "linux" ]]; then