Merge pull request kelvins#325 from Hardvan/subsets-bit-manipulation

Add Subsets using Bit Manipulation

Author: kelvins

README.md

@@ -3608,6 +3608,64 @@ In order to achieve greater coverage and encourage more people to contribute to
                 </a>
             </td>
         </tr>
+        <tr>
+            <td>Subsets Bit Manipulation</td>
+            <td> <!-- C -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- C++ -->
+                <a href="./src/cpp/SubsetsBitManipulation.cpp">
+                    <img align="center" height="25" src="./logos/cplusplus.svg" />
+                </a>
+            </td>
+            <td> <!-- Java -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Python -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Go -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Ruby -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- JavaScript -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Swift -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Rust -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Scala -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+            <td> <!-- Kotlin -->
+                <a href="./CONTRIBUTING.md">
+                    <img align="center" height="25" src="./logos/github.svg" />
+                </a>
+            </td>
+        </tr>
         <tr>
             <td>Two-Sum Problem</td>
             <td> <!-- C -->

src/cpp/SubsetsBitManipulation.cpp

@@ -0,0 +1,62 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+/*
+Problem Statement:
+Given an integer array nums of unique elements, return all possible
+subsets (the power set).
+
+The solution set must not contain duplicate subsets. Return the solution in any order.
+*/
+
+// Using Bit Manipulation
+// 1) Traverse all subsets
+// 2) Traverse all elements of nums
+// 3) Check if jth bit is set in i
+// It is like for 3 elements:
+// 000, 001, 010, 011, 100, 101, 110, 111
+// where 1 means that element is present in the subset
+// Time: O(n * 2ⁿ)
+// Space: O(1)
+vector<vector<int>> subsets(vector<int> &nums)
+{
+    int n = nums.size();
+    int total = 1 << n; // 2ⁿ
+    vector<vector<int>> ans(total);
+
+    // Traverse all subsets
+    for (int i = 0; i < total; i++) // 2ⁿ
+    {
+        // Traverse elements of nums
+        for (int j = 0; j < n; j++) // n
+        {
+            // Check if jth bit is set in i
+            if ((1 << j) & i)
+            {
+                ans[i].push_back(nums[j]);
+            }
+        }
+    }
+
+    return ans;
+}
+
+int main()
+{
+    vector<int> nums = {1, 2, 3};
+    vector<vector<int>> ans = subsets(nums);
+
+    cout << "Subsets are: \n";
+    for (auto v : ans)
+    {
+        cout << "[ ";
+        for (auto i : v)
+        {
+            cout << i << " ";
+        }
+        cout << "]\n";
+    }
+
+    return 0;
+}