From 2729caa4e1bd4732cde519020cbe37de17249dd2 Mon Sep 17 00:00:00 2001
From: Holychung <mickey94378@gmail.com>
Date: Wed, 18 May 2022 22:02:56 +0800
Subject: [PATCH] Create combination-sum.cpp

---
 C++/combination-sum.cpp | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 C++/combination-sum.cpp

diff --git a/C++/combination-sum.cpp b/C++/combination-sum.cpp
new file mode 100644
index 0000000000..290da258ff
--- /dev/null
+++ b/C++/combination-sum.cpp
@@ -0,0 +1,27 @@
+// Time:  O(k * n^k)
+// Space: O(k)
+
+class Solution {
+  vector<vector<int>> ans;
+  void findCombinations(vector<int> &candidates, int begin, vector<int> &sol, int target) {
+    if (target < 0)
+      return;
+    if (target == 0) {
+      ans.push_back(sol);
+      return;
+    }
+    for (int i = begin; i < candidates.size(); i++) {
+      sol.push_back(candidates[i]);
+      findCombinations(candidates, i, sol, target - candidates[i]);
+      sol.pop_back();
+    }
+  }
+
+public:
+  vector<vector<int>> combinationSum(vector<int> &candidates, int target) {
+    ans = {};
+    vector<int> sol = {};
+    findCombinations(candidates, 0, sol, target);
+    return ans;
+  }
+};
\ No newline at end of file