Create: 0077-combinations.cpp

Author: tapasyadimree

cpp/0077-combinations.cpp

@@ -0,0 +1,27 @@
+class Solution {
+private:
+    void backtrack(int start, int n, int k, vector<int> &combination, vector<vector<int>> &res){
+            //base case, when size of combination is k, we wanna stop
+            if(combination.size() == k){
+                res.push_back(combination);
+                return;
+            }
+
+            for(int i = start; i<=n; i++){
+                combination.push_back(i);
+                backtrack(i+1, n, k, combination, res);
+                combination.pop_back();
+            }
+        }
+public:
+    vector<vector<int>> combine(int n, int k) {
+        vector<vector<int>> res;
+
+        //initial empty list to pass to the backtrack function
+        vector<int> emptyCombination;
+
+        backtrack(1, n, k, emptyCombination, res);
+
+        return res;
+    }
+};