From 6290a6264a32632ca0e576fd694a8b20105d138b Mon Sep 17 00:00:00 2001
From: moaldeen <132774635+moaldeen@users.noreply.github.com>
Date: Wed, 15 Nov 2023 02:08:24 -0500
Subject: [PATCH 1/6] Update all_combinations.py

The original implementation had limitations in handling edge cases and certain input parameters, leading to potential RecursionError.
---
 backtracking/all_combinations.py | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/backtracking/all_combinations.py b/backtracking/all_combinations.py
index ecbcc5882ec1..909eca256798 100644
--- a/backtracking/all_combinations.py
+++ b/backtracking/all_combinations.py
@@ -36,6 +36,8 @@ def generate_all_combinations(n: int, k: int) -> list[list[int]]:
     ...     for n in range(1, 6) for k in range(1, 6))
     True
     """
+    if k < 0 or n < 0 or k > n:
+        return []  # Return an empty list for invalid input
 
     result: list[list[int]] = []
     create_all_state(1, n, k, [], result)
@@ -53,7 +55,7 @@ def create_all_state(
         total_list.append(current_list[:])
         return
 
-    for i in range(increment, total_number - level + 2):
+    for i in range(increment, total_number + 1):
         current_list.append(i)
         create_all_state(i + 1, total_number, level - 1, current_list, total_list)
         current_list.pop()

From dae4f8690cf001dd97e3dd75a33bf2a06f4734ef Mon Sep 17 00:00:00 2001
From: moaldeen <132774635+moaldeen@users.noreply.github.com>
Date: Wed, 15 Nov 2023 02:22:26 -0500
Subject: [PATCH 2/6] Update all_combinations.py

Added checks to handle cases where n or k are negative or where k is greater than n. In such scenarios, the function now returns an empty list, avoiding invalid recursive calls.
---
 backtracking/all_combinations.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/backtracking/all_combinations.py b/backtracking/all_combinations.py
index 909eca256798..0514cb58bb64 100644
--- a/backtracking/all_combinations.py
+++ b/backtracking/all_combinations.py
@@ -55,7 +55,7 @@ def create_all_state(
         total_list.append(current_list[:])
         return
 
-    for i in range(increment, total_number + 1):
+    i in range(increment, total_number - level + 2):
         current_list.append(i)
         create_all_state(i + 1, total_number, level - 1, current_list, total_list)
         current_list.pop()

From 60206f6bdee11a519f9f881c124fcd0acd49201d Mon Sep 17 00:00:00 2001
From: moaldeen <132774635+moaldeen@users.noreply.github.com>
Date: Wed, 15 Nov 2023 02:26:05 -0500
Subject: [PATCH 3/6] Update error handling

Added checks to handle cases where `n` or `k` are negative or where `k` is greater than `n`. In such scenarios, the function now returns an empty list, avoiding invalid recursive calls.
---
 backtracking/all_combinations.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/backtracking/all_combinations.py b/backtracking/all_combinations.py
index 0514cb58bb64..587c6509decb 100644
--- a/backtracking/all_combinations.py
+++ b/backtracking/all_combinations.py
@@ -55,7 +55,7 @@ def create_all_state(
         total_list.append(current_list[:])
         return
 
-    i in range(increment, total_number - level + 2):
+    for i in range(increment, total_number - level + 2):
         current_list.append(i)
         create_all_state(i + 1, total_number, level - 1, current_list, total_list)
         current_list.pop()

From 32a74df2bdde4a96ab6db7a5b9467e57e3992368 Mon Sep 17 00:00:00 2001
From: Christian Clauss <cclauss@me.com>
Date: Sat, 25 Nov 2023 14:18:54 +0100
Subject: [PATCH 4/6] Update backtracking/all_combinations.py

---
 backtracking/all_combinations.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/backtracking/all_combinations.py b/backtracking/all_combinations.py
index 587c6509decb..a2ece4711ea2 100644
--- a/backtracking/all_combinations.py
+++ b/backtracking/all_combinations.py
@@ -36,8 +36,12 @@ def generate_all_combinations(n: int, k: int) -> list[list[int]]:
     ...     for n in range(1, 6) for k in range(1, 6))
     True
     """
-    if k < 0 or n < 0 or k > n:
-        return []  # Return an empty list for invalid input
+    if k < 0:
+        raise ValueError("k must not be negative")
+    if n < 0:
+        raise ValueError("n must not be negative")
+    if k > n:
+        raise ValueError("k must less that or equal to n")
 
     result: list[list[int]] = []
     create_all_state(1, n, k, [], result)

From e2990eaab859e714348a65633dbfb1b2544d1c82 Mon Sep 17 00:00:00 2001
From: Christian Clauss <cclauss@me.com>
Date: Sat, 25 Nov 2023 14:22:32 +0100
Subject: [PATCH 5/6] Update all_combinations.py

---
 backtracking/all_combinations.py | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/backtracking/all_combinations.py b/backtracking/all_combinations.py
index a2ece4711ea2..2cc9e5f02b8e 100644
--- a/backtracking/all_combinations.py
+++ b/backtracking/all_combinations.py
@@ -26,9 +26,15 @@ def generate_all_combinations(n: int, k: int) -> list[list[int]]:
     >>> generate_all_combinations(n=10, k=-1)
     Traceback (most recent call last):
         ...
-    RecursionError: maximum recursion depth exceeded
+    ValueError: k must not be negative
     >>> generate_all_combinations(n=-1, k=10)
-    []
+    Traceback (most recent call last):
+        ...
+    ValueError: n must not be negative
+    >>> generate_all_combinations(n=0, k=1)
+    Traceback (most recent call last):
+        ...
+    ValueError: k must be less than or equal to n
     >>> generate_all_combinations(n=5, k=4)
     [[1, 2, 3, 4], [1, 2, 3, 5], [1, 2, 4, 5], [1, 3, 4, 5], [2, 3, 4, 5]]
     >>> from itertools import combinations
@@ -41,7 +47,7 @@ def generate_all_combinations(n: int, k: int) -> list[list[int]]:
     if n < 0:
         raise ValueError("n must not be negative")
     if k > n:
-        raise ValueError("k must less that or equal to n")
+        raise ValueError("k must be less than or equal to n")
 
     result: list[list[int]] = []
     create_all_state(1, n, k, [], result)

From 674901c7c88f8b356fdde38070a06746c83ae17c Mon Sep 17 00:00:00 2001
From: Christian Clauss <cclauss@me.com>
Date: Sat, 25 Nov 2023 14:28:45 +0100
Subject: [PATCH 6/6] Apply suggestions from code review

---
 backtracking/all_combinations.py | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/backtracking/all_combinations.py b/backtracking/all_combinations.py
index 2cc9e5f02b8e..407304948c39 100644
--- a/backtracking/all_combinations.py
+++ b/backtracking/all_combinations.py
@@ -31,10 +31,6 @@ def generate_all_combinations(n: int, k: int) -> list[list[int]]:
     Traceback (most recent call last):
         ...
     ValueError: n must not be negative
-    >>> generate_all_combinations(n=0, k=1)
-    Traceback (most recent call last):
-        ...
-    ValueError: k must be less than or equal to n
     >>> generate_all_combinations(n=5, k=4)
     [[1, 2, 3, 4], [1, 2, 3, 5], [1, 2, 4, 5], [1, 3, 4, 5], [2, 3, 4, 5]]
     >>> from itertools import combinations
@@ -46,8 +42,6 @@ def generate_all_combinations(n: int, k: int) -> list[list[int]]:
         raise ValueError("k must not be negative")
     if n < 0:
         raise ValueError("n must not be negative")
-    if k > n:
-        raise ValueError("k must be less than or equal to n")
 
     result: list[list[int]] = []
     create_all_state(1, n, k, [], result)