From a047db4e1579d88d5d4035bcbc37eff2931146ff Mon Sep 17 00:00:00 2001
From: Evan Ferrao <evanferrao@gmail.com>
Date: Thu, 5 Feb 2026 17:51:14 +0530
Subject: [PATCH] update and improve combination and subset

---
 Recursion/CombinationTwo.java                 |  3 +-
 Recursion/CombinationTwoAlternate.java        | 73 +++++++++++++++++++
 Recursion/SubsetTwo.java                      | 41 +++++++++++
 ...uplicates.java => SubsetTwoAlternate.java} |  4 +-
 Recursion/{Subset.java => SubsetsOne.java}    |  4 +-
 SubsetsTwo.java                               |  0
 6 files changed, 122 insertions(+), 3 deletions(-)
 create mode 100644 Recursion/CombinationTwoAlternate.java
 create mode 100644 Recursion/SubsetTwo.java
 rename Recursion/{SubsetsWithoutDuplicates.java => SubsetTwoAlternate.java} (93%)
 rename Recursion/{Subset.java => SubsetsOne.java} (93%)
 create mode 100644 SubsetsTwo.java

diff --git a/Recursion/CombinationTwo.java b/Recursion/CombinationTwo.java
index 00c094a..7b41866 100644
--- a/Recursion/CombinationTwo.java
+++ b/Recursion/CombinationTwo.java
@@ -1,5 +1,6 @@
 // https://leetcode.com/problems/combination-sum-ii/
-import java.util.*;
+i
+mport java.util.*;
 
 class CombinationTwo {
 
diff --git a/Recursion/CombinationTwoAlternate.java b/Recursion/CombinationTwoAlternate.java
new file mode 100644
index 0000000..02e9c88
--- /dev/null
+++ b/Recursion/CombinationTwoAlternate.java
@@ -0,0 +1,73 @@
+// https://leetcode.com/problems/combination-sum-ii/
+
+import java.util.*;
+
+class CombinationTwoAlternate {
+
+    public static void findCombination(int currentIndex, List<Integer> ds,
+                                       int[] candidates, int n, int target,
+                                       List<List<Integer>> finalAnswer){
+
+        // If target reached
+        if (target == 0){
+            finalAnswer.add(new ArrayList<>(ds));
+            return;
+        }
+
+        // If out of bounds OR target becomes negative
+        if (currentIndex == n || target < 0){
+            return;
+        }
+
+        // ---------------- INCLUDE ----------------
+        if (candidates[currentIndex] <= target){
+            ds.add(candidates[currentIndex]);
+
+            // Move to next index (no reuse allowed)
+            findCombination(currentIndex + 1, ds, candidates, n,
+                            target - candidates[currentIndex], finalAnswer);
+
+            ds.remove(ds.size() - 1);
+        }
+
+        // ---------------- EXCLUDE ----------------
+        int nextIndex = currentIndex + 1;
+
+        // Skip duplicates
+        while(nextIndex < n && candidates[nextIndex] == candidates[currentIndex]){
+            nextIndex++;
+        }
+
+        findCombination(nextIndex, ds, candidates, n, target, finalAnswer);
+    }
+
+    public List<List<Integer>> combinationSum2(int[] candidates, int target){
+
+        Arrays.sort(candidates);
+
+        List<List<Integer>> finalAnswer = new ArrayList<>();
+        findCombination(0, new ArrayList<>(), candidates,
+                        candidates.length, target, finalAnswer);
+
+        return finalAnswer;
+    }
+}
+
+
+public class Main {
+
+    public static void main(String[] args){
+
+        int[] candidates = {1,1,1,2,2};
+        int target = 4;
+
+        Solution sol = new Solution();
+
+        List<List<Integer>> result = sol.combinationSum2(candidates, target);
+
+        System.out.println("Unique Combinations:");
+        for(List<Integer> list : result){
+            System.out.println(list);
+        }
+    }
+}
diff --git a/Recursion/SubsetTwo.java b/Recursion/SubsetTwo.java
new file mode 100644
index 0000000..ca7aa97
--- /dev/null
+++ b/Recursion/SubsetTwo.java
@@ -0,0 +1,41 @@
+// https://leetcode.com/problems/subsets-ii/submissions/1909073945/
+
+import java.util.*;
+
+class SubsetTwo {
+
+    public void findSubsets(int ind, int[] nums, List<Integer> ds, List<List<Integer>> ansList) {
+        ansList.add(new ArrayList<>(ds));
+
+        for (int i = ind; i < nums.length; i++) {
+            if (i != ind && nums[i] == nums[i - 1]) continue;
+
+            ds.add(nums[i]);
+            findSubsets(i + 1, nums, ds, ansList);
+            ds.remove(ds.size() - 1);
+        }
+    }
+
+    public List<List<Integer>> subsetsWithDup(int[] nums) {
+        Arrays.sort(nums);
+        List<List<Integer>> ansList = new ArrayList<>();
+        findSubsets(0, nums, new ArrayList<>(), ansList);
+        return ansList;
+    }
+}
+
+public class Main {
+    public static void main(String[] args) {
+
+        // Assumed Input
+        int[] nums = {1, 2, 2};
+
+        Solution sol = new Solution();
+        List<List<Integer>> result = sol.subsetsWithDup(nums);
+
+        System.out.println("Subsets Without Duplicates:");
+        for (List<Integer> subset : result) {
+            System.out.println(subset);
+        }
+    }
+}
diff --git a/Recursion/SubsetsWithoutDuplicates.java b/Recursion/SubsetTwoAlternate.java
similarity index 93%
rename from Recursion/SubsetsWithoutDuplicates.java
rename to Recursion/SubsetTwoAlternate.java
index 8cd9e00..38733ad 100644
--- a/Recursion/SubsetsWithoutDuplicates.java
+++ b/Recursion/SubsetTwoAlternate.java
@@ -1,6 +1,8 @@
+// https://leetcode.com/problems/subsets-ii/submissions/1909073945/
+
 import java.util.*;
 
-class SubsetsWithoutDuplicates {
+class SubsetTwoAlternate {
 
     public static void printSubset(int currentIndex, List<Integer> ds, int[] nums, int n, List<List<Integer>> finalAnswer){
         if (currentIndex == n){
diff --git a/Recursion/Subset.java b/Recursion/SubsetsOne.java
similarity index 93%
rename from Recursion/Subset.java
rename to Recursion/SubsetsOne.java
index 194c1d6..c7e638e 100644
--- a/Recursion/Subset.java
+++ b/Recursion/SubsetsOne.java
@@ -1,6 +1,8 @@
+// https://leetcode.com/problems/subsets/description/
+
 import java.util.*;
 
-public class Subset {
+public class SubsetsOne {
 
     public static void printSubset(int currentIndex, List<Integer> ds, int[] nums, int n, List<List<Integer>> finalAnswer){
         if (currentIndex == n){
diff --git a/SubsetsTwo.java b/SubsetsTwo.java
new file mode 100644
index 0000000..e69de29