Permutations

Author: Shikha-code36

Backtracking/46-Permutations.py

@@ -0,0 +1,30 @@
+'''
+                                Permutations
+Given an array nums of distinct integers, return all the possible permutations. You can return the answer in any order.
+
+Example 1:
+
+Input: nums = [1,2,3]
+Output: [[1,2,3],[1,3,2],[2,1,3],[2,3,1],[3,1,2],[3,2,1]]
+'''
+
+
+def permute(nums):
+    result = []
+
+    # base case
+    if len(nums) == 1:
+        return [nums.copy()] #ornums[:] is a deep copy
+
+    for i in range(len(nums)):
+        n = nums.pop()
+        perms = permute(nums)
+
+        for perm in perms:
+            perm.append(n)
+        result.extend(perms)
+        nums.append(n)
+    return result
+
+#T:O(2^n)
+#S:O(n)

README.md

@@ -10,4 +10,5 @@ Check the notes for the explaination - [Notes](https://stingy-shallot-4ea.notion
     - [x] [Letter Case Permutation](Backtracking/784-letter-case-permutation.py)
     - [x] [Subsets](Backtracking/78-Subsets.py)
     - [x] [Subsets-II](Backtracking/78-Subsets.py)
+    - [x] [Permutations](Backtracking/46-Permutations.py)