From 593196dcc3db2f6ba84429a307aa98c2f5c0400d Mon Sep 17 00:00:00 2001
From: Pandz18 <58665834+Pandz18@users.noreply.github.com>
Date: Mon, 26 Oct 2020 18:43:06 +0530
Subject: [PATCH 1/3] Create Perm_Recus.java

---
 Java/Perm_Recus.java | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 Java/Perm_Recus.java

diff --git a/Java/Perm_Recus.java b/Java/Perm_Recus.java
new file mode 100644
index 00000000..89d051c4
--- /dev/null
+++ b/Java/Perm_Recus.java
@@ -0,0 +1,28 @@
+public List<List<Integer>> permute(int[] nums) {
+    List<List<Integer>> result = new ArrayList<>();
+    helper(0, nums, result);
+    return result;
+}
+ 
+private void helper(int start, int[] nums, List<List<Integer>> result){
+    if(start==nums.length-1){
+        ArrayList<Integer> list = new ArrayList<>();
+        for(int num: nums){
+            list.add(num);
+        }
+        result.add(list);
+        return;
+    }
+ 
+    for(int i=start; i<nums.length; i++){
+        swap(nums, i, start);
+        helper(start+1, nums, result);
+        swap(nums, i, start);
+    }
+}
+ 
+private void swap(int[] nums, int i, int j){
+    int temp = nums[i];
+    nums[i] = nums[j];
+    nums[j] = temp;
+}

From d58ff89fc7473021995a44d21db59011eb69200b Mon Sep 17 00:00:00 2001
From: Pandz18 <58665834+Pandz18@users.noreply.github.com>
Date: Mon, 26 Oct 2020 18:51:44 +0530
Subject: [PATCH 2/3] Update Perm_Recus.java

---
 Java/Perm_Recus.java | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/Java/Perm_Recus.java b/Java/Perm_Recus.java
index 89d051c4..40b3a9a6 100644
--- a/Java/Perm_Recus.java
+++ b/Java/Perm_Recus.java
@@ -4,25 +4,29 @@ public List<List<Integer>> permute(int[] nums) {
     return result;
 }
  
-private void helper(int start, int[] nums, List<List<Integer>> result){
+private void helper(int start, int[] nums, List<List<Integer>> result)
+{
     if(start==nums.length-1){
-        ArrayList<Integer> list = new ArrayList<>();
-        for(int num: nums){
+        ArrayList<Integer> list = new ArrayList<>(); //if starting value(say n) is the last value , this will make a new list with the values and the new starting value is n
+        for(int num: nums)
+        {
             list.add(num);
         }
         result.add(list);
         return;
     }
  
-    for(int i=start; i<nums.length; i++){
+    for(int i=start; i<nums.length; i++)      //a loop to keep on swapping as many times as there are values in the list 
+    {
         swap(nums, i, start);
         helper(start+1, nums, result);
         swap(nums, i, start);
     }
 }
  
-private void swap(int[] nums, int i, int j){
-    int temp = nums[i];
+private void swap(int[] nums, int i, int j)
+{
+    int temp = nums[i];      //temp temporarily holds the value of nums so that i & j values can be exchanged
     nums[i] = nums[j];
     nums[j] = temp;
 }

From 50dea5beff1ca52b95bd2cfa0981e3e21ab53ca5 Mon Sep 17 00:00:00 2001
From: Pandz18 <58665834+Pandz18@users.noreply.github.com>
Date: Mon, 26 Oct 2020 20:42:30 +0530
Subject: [PATCH 3/3] Updated

---
 README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/README.md b/README.md
index bf4abc1c..02cdbc4f 100644
--- a/README.md
+++ b/README.md
@@ -124,7 +124,7 @@ Check out ---> [Sample PR](https://github.com/codedecks-in/LeetCode-Solutions/pu
 | 189     | [Rotate-Array](https://leetcode.com/problems/rotate-array/)                                                                   | [Python](./Python/rotate-array.py)                                                                                | O(N)         | O(1)          | Medium     | Array              |
 | 496     | [next-greater-element-i](https://leetcode.com/problems/next-greater-element-i)                                                | [Python](./Python/496_nextgreaterelement.py)                                                                      | O(N)         | O(1)          | Medium     | Array              |
 | 1470    | [Shuffle the Array](https://leetcode.com/problems/shuffle-the-array)                                                          | [Java](./Java/shuffle-the-array.java)                                                                             | O(N)         | O(1)          | Easy       | Array              |
-
+| 124  | [Permutation by Recussion](https://leetcode.com/problems/permutations/)                                                          | [Java](./Java/shuffle-the-array.java)                                                                             | O(N)         | O(N)          | Easy       | Array              |
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