day 15: 78-subsets

78-subsets/driver.cpp

@@ -0,0 +1,15 @@
+#include "soln.hpp"
+
+int main()	{
+	vector<int> nums{1,2,3};
+	Solution soln;
+	vector<vector<int>> answer = soln.subsets(nums);
+	for(int i = 0; i < answer.size(); i++)	{
+		cout << "Subset " << (i+1) << ": ";
+		for(int j = 0; j < answer[i].size(); j++)	{
+			cout << answer[i][j] << " ";
+		}
+		cout << endl;
+	}
+	return 0;
+}

78-subsets/soln.cpp

@@ -0,0 +1,19 @@
+#include "soln.hpp"
+
+vector<vector<int>> Solution::subsets(vector<int> &nums)
+{
+	int num_combos = 1 << nums.size();
+	vector<vector<int>> subs(num_combos);
+	for (int i = 0; i < num_combos; i++)
+	{
+		for (int j = 0; j < nums.size(); j++)
+		{
+			// check if this index exists in this combo
+			if ((i >> j) & 1)
+			{
+				subs[i].push_back(nums[j]);
+			}
+		}
+	}
+	return subs;
+}

78-subsets/soln.hpp

@@ -0,0 +1,7 @@
+#include <bits/stdc++.h>
+using namespace std;
+class Solution
+{
+public:
+	vector<vector<int>> subsets(vector<int> &nums);
+};