change implementation to insertion-sort

sorting.cpp

@@ -2,13 +2,19 @@
 using namespace std ;
 vector<int> sort_custom(vector<int> data)
 {
-	vector<int> arr(data.begin(), data.end()) ;
-	for(int i = 0; i < data.size(); i++)
+	int i, key, j;
+	vector<int> ans = data;
+   for (i = 1; i < data.size(); i++)
    {
-		for(int j = 0; j < data.size()-i-1; j++)
+       key = ans[i];
+       j = i-1;
+       while (j >= 0 && ans[j] > key)
        {
-			if (arr[j] > arr[j+1]) swap(arr[j],arr[j+1]) ;
+           ans[j+1] = ans[j];
+           j = j-1;
        }
+       ans[j+1] = key;
    }
-	return arr ;
+   return ans;
 }
+