find unique id

Author: pwgraham91

find_unique_id.py

@@ -0,0 +1,140 @@
+"""
+Given the list of IDs, which contains many duplicate integers and one unique integer, find the unique integer.
+https://www.interviewcake.com/question/python/find-unique-int-among-duplicates
+"""
+
+import random
+
+
+def generate_log():
+    original_list = list(range(1, 11))
+    return_list = original_list.copy()
+    return_list.pop(3)
+    log = original_list + return_list
+    random.shuffle(log)
+    return log
+
+
+def find_unique_id_cycling(log):
+    """
+    time complexity: n^2
+    space complexity: 1
+    """
+    comparison_count = 0
+    for checking in log:
+        found_instances = 0
+
+        for comparison in log:
+            comparison_count += 1
+            if checking == comparison:
+                found_instances += 1
+
+        if found_instances == 1:
+            print(comparison_count)
+            return checking
+
+
+def find_unique_cycling_reduction(log):
+    """
+    time complexity: (((n-1) / 2) ^ 2) + (n-1) / 2
+    space complexity: 1
+    """
+    copied_log = log.copy()
+    comparison_count = 0
+
+    while len(copied_log) > 0:
+        checking = copied_log[0]
+        for i in range(1, len(copied_log)):
+            comparison = copied_log[i]
+            comparison_count += 1
+            if checking == comparison:
+                # remove the found ids from the copied list
+                copied_log.pop(i)
+                copied_log.pop(0)
+                break
+        else:
+            print(comparison_count)
+            return checking
+
+
+def find_unique_dict(log):
+    """
+    time complexity: n
+    space complexity: n
+    """
+    duplicate_dict = {}
+    for i in log:
+        if duplicate_dict.get(i):
+            duplicate_dict.pop(i)
+        else:
+            duplicate_dict[i] = 1
+    return list(duplicate_dict)[0]
+
+
+def find_unique_sort(log):
+    """
+    time complexity: nlogn + (n-1)
+    space complexity: n
+    """
+    sorted_log = sorted(log)
+    for a in range(len(log)):
+        try:
+            if sorted_log[0] == sorted_log[1]:
+                sorted_log.pop(1)
+                sorted_log.pop(0)
+            else:
+                return sorted_log[a]
+        except IndexError:
+            return sorted_log[0]
+
+
+def find_unique_crazy_xor(delivery_ids):
+    """
+    time complexity: n
+    space complexity: 1
+    """
+
+    unique_delivery_id = 0
+
+    for delivery_id in delivery_ids:
+        unique_delivery_id ^= delivery_id
+
+    return unique_delivery_id
+
+
+test_list = [4, 3, 7, 2, 6, 5, 9, 9, 2, 7, 8, 5, 1, 8, 1, 3, 10, 6, 10]
+print('cycling beginning of the list: n where n={}'.format(len(test_list)))
+print('result: ', find_unique_id_cycling(test_list))
+
+test_list = [3, 7, 2, 6, 5, 9, 9, 2, 7, 8, 5, 1, 8, 1, 3, 10, 6, 10, 4]
+print('cycling end of the list: n^2 . where n={}'.format(len(test_list)))
+print('result: ', find_unique_id_cycling(test_list))
+
+test_list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 9, 8, 7, 6, 5, 4, 3, 2, 1, 10]
+print('cycling end of the palindromic list, n^2 . where n={}'.format(len(test_list)))
+print('result: ', find_unique_id_cycling(test_list))
+
+test_list = [4, 3, 7, 2, 6, 5, 9, 9, 2, 7, 8, 5, 1, 8, 1, 3, 10, 6, 10]
+print('reduction beginning of the list, n . where n={}'.format(len(test_list)))
+print('result: ', find_unique_cycling_reduction(test_list))
+
+test_list = [3, 7, 2, 6, 5, 9, 9, 2, 7, 8, 5, 1, 8, 1, 3, 10, 6, 10, 4]
+print('reduction end of the list, random . where n={}'.format(len(test_list)))
+print('result: ', find_unique_cycling_reduction(test_list))
+
+test_list = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1]
+print('reduction worst case, (((n-1) / 2) ^ 2) + (n-1) / 2 . where n={}'.format(len(test_list)))
+print('result: ', find_unique_cycling_reduction(test_list))
+
+test_list = [1, 2, 3, 4, 5, 6, 7, 8, 7, 6, 5, 4, 3, 2, 1]
+print('reduction worst case, (((n-1) / 2) ^ 2) + (n-1) / 2 . where n={}'.format(len(test_list)))
+print('result: ', find_unique_cycling_reduction(test_list))
+
+print('dict worst case, n where n={}'.format(len(test_list)))
+print('result: ', find_unique_dict(test_list))
+
+print('sort worst case, nlog(n) + (n-1) where n={}'.format(len(test_list)))
+print('result: ', find_unique_sort(test_list))
+
+print('xor worst case, n where n={}'.format(len(test_list)))
+print('result: ', find_unique_crazy_xor(test_list))