Add some cool queue, stacks, strings, math, bit manipulation examples (#35)

arrays_and_strings/permutation.py

@@ -0,0 +1,22 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+# author: bt3gl
+
+
+def permutation(string) -> list:
+
+    if len(string) == 1:
+        return [string]
+    
+    result = []
+    for i, char in enumerate(string):
+        for perm in permutation(string[:i] + string[i+1:]):
+            result += [char + perm]
+    
+    return result
+
+
+if __name__ == '__main__':
+    print('Testing permutation()...')
+    string = "bt3gl"
+    print(f'Permutation of {string}: {permutation(string)}')