Added problem in Backtracking and DynamicProgramming

Author: Prashant Jain

src/in/knowledgegate/dsa/backtracking/Subsets.java

@@ -0,0 +1,57 @@
+package in.knowledgegate.dsa.backtracking;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * SAME PROBLEM IS SOLVED IN DP ALSO
+ * <p>
+ * Given an integer array nums of unique elements,
+ * return all possible subsets (the power set).
+ * <p>
+ * The solution set must not contain duplicate
+ * subsets. Return the solution in any order.
+ * <p>
+ * Example 1: Input: nums = [1,2,3] Output:
+ * [[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]]
+ * <p>
+ * Example 2: Input: nums = [0] Output: [[],[0]]
+ * <p>
+ * Constraints: 1 <= nums.length <= 10 -10 <=
+ * nums[i] <= 10 All the numbers of nums are
+ * unique.
+ */
+public class Subsets {
+  public static void main(String[] args) {
+    Subsets subsets = new Subsets();
+    int[] nums = new int[]{};
+    System.out.println("PowerSet is :" +
+        subsets.subsets(nums));
+  }
+
+  public List<List<Integer>> subsets(int[] nums) {
+    List<List<Integer>> output = new ArrayList<>();
+    for (int i = 0; i <= nums.length; i++) {
+      backtrack(output, i, 0, new ArrayList<>(),
+          nums);
+    }
+    return output;
+  }
+
+  private void backtrack(List<List<Integer>> output,
+    int length, int beg, List<Integer> curr,
+    int[] nums) {
+
+    if (curr.size() == length) {
+      output.add(new ArrayList<>(curr));
+      return;
+    }
+
+    for (int i = beg; i < nums.length; i++) {
+      curr.add(nums[i]);
+      backtrack(output, length, i + 1, curr,
+          nums);
+      curr.remove(curr.size() - 1);
+    }
+  }
+}

src/in/knowledgegate/dsa/dynamicprogramming/Subsets.java

@@ -0,0 +1,47 @@
+package in.knowledgegate.dsa.dynamicprogramming;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * SAME PROBLEM IS SOLVED IN BACKTRACKING ALSO
+ * <p>
+ * Given an integer array nums of unique elements,
+ * return all possible subsets (the power set).
+ * <p>
+ * The solution set must not contain duplicate
+ * subsets. Return the solution in any order.
+ * <p>
+ * Example 1: Input: nums = [1,2,3] Output:
+ * [[],[1],[2],[1,2],[3],[1,3],[2,3], [1,2,3]]
+ * <p>
+ * Example 2: Input: nums = [0] Output: [[],[0]]
+ * <p>
+ * Constraints: 1 <= nums.length <= 10 -10 <=
+ * nums[i] <= 10 All the numbers of nums are
+ * unique.
+ */
+public class Subsets {
+  public static void main(String[] args) {
+    Subsets subsets = new Subsets();
+    int[] nums = new int[]{1, 2, 3, 4};
+    System.out.println("PowerSet is:" +
+        subsets.subsets(nums));
+  }
+
+  public List<List<Integer>> subsets(int[] nums) {
+    List<List<Integer>> res = new ArrayList<>();
+    res.add(new ArrayList<>());
+
+    for (int num : nums) {
+      int length = res.size();
+      for (int i = 0; i < length; i++) {
+        List<Integer> copy =
+            new ArrayList<>(res.get(i));
+        copy.add(num);
+        res.add(copy);
+      }
+    }
+    return res;
+  }
+}