From 5a8655d306d872085112d965067fcdc440286928 Mon Sep 17 00:00:00 2001
From: 1227haran <68032825+1227haran@users.noreply.github.com>
Date: Sat, 5 Oct 2024 22:49:58 +0530
Subject: [PATCH] Added new algorithm to generate numbers in lexicographical
 order (#11674)

* Added algorithm to generate numbers in lexicographical order

* Removed the test cases

* Updated camelcase to snakecase

* Added doctest

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Added descriptive name for n

* Reduced the number of letters

* Updated the return type

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Updated import statement

* Updated return type to Iterator[int]

* removed parentheses

---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
---
 .../stacks/lexicographical_numbers.py         | 38 +++++++++++++++++++
 1 file changed, 38 insertions(+)
 create mode 100644 data_structures/stacks/lexicographical_numbers.py

diff --git a/data_structures/stacks/lexicographical_numbers.py b/data_structures/stacks/lexicographical_numbers.py
new file mode 100644
index 000000000..6a174e7d9
--- /dev/null
+++ b/data_structures/stacks/lexicographical_numbers.py
@@ -0,0 +1,38 @@
+from collections.abc import Iterator
+
+
+def lexical_order(max_number: int) -> Iterator[int]:
+    """
+    Generate numbers in lexical order from 1 to max_number.
+
+    >>> " ".join(map(str, lexical_order(13)))
+    '1 10 11 12 13 2 3 4 5 6 7 8 9'
+    >>> list(lexical_order(1))
+    [1]
+    >>> " ".join(map(str, lexical_order(20)))
+    '1 10 11 12 13 14 15 16 17 18 19 2 20 3 4 5 6 7 8 9'
+    >>> " ".join(map(str, lexical_order(25)))
+    '1 10 11 12 13 14 15 16 17 18 19 2 20 21 22 23 24 25 3 4 5 6 7 8 9'
+    >>> list(lexical_order(12))
+    [1, 10, 11, 12, 2, 3, 4, 5, 6, 7, 8, 9]
+    """
+
+    stack = [1]
+
+    while stack:
+        num = stack.pop()
+        if num > max_number:
+            continue
+
+        yield num
+        if (num % 10) != 9:
+            stack.append(num + 1)
+
+        stack.append(num * 10)
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()
+    print(f"Numbers from 1 to 25 in lexical order: {list(lexical_order(26))}")