Sliding window max (peeked a bit)

leetcode/pyproject.toml

@@ -13,27 +13,14 @@ keywords = []
 authors = [
   { name = "Dan Buch", email = "dan@meatballhat.com" },
 ]
-classifiers = [
-  "Development Status :: 4 - Beta",
-  "Programming Language :: Python",
-  "Programming Language :: Python :: 3.7",
-  "Programming Language :: Python :: 3.8",
-  "Programming Language :: Python :: 3.9",
-  "Programming Language :: Python :: 3.10",
-  "Programming Language :: Python :: 3.11",
-  "Programming Language :: Python :: Implementation :: CPython",
-  "Programming Language :: Python :: Implementation :: PyPy",
-]
+classifiers = []
 dependencies = [
   "ipython",
-  "ipdb"
+  "ipdb",
+  "matplotlib",
+  "numpy"
 ]
 
-[project.urls]
-Documentation = "https://github.com/unknown/leetcode#readme"
-Issues = "https://github.com/unknown/leetcode/issues"
-Source = "https://github.com/unknown/leetcode"
-
 [tool.hatch.envs.default]
 dependencies = [
   "coverage[toml]>=6.5",

leetcode/stuff.py

@@ -1,4 +1,6 @@
 import copy
+import itertools
+import math
 import random
 import typing
 
@@ -538,19 +540,31 @@ def copy_random_list(
 
 
 def sum_max_sub_array(nums: list[int]) -> int:
-    window_size: int = 1
-    begin: int = 0
-    end: int = window_size
-    max_sum: int = sum(nums)
-
-    while end - begin <= len(nums):
-        while end <= len(nums):
-            max_sum = max(max_sum, sum(nums[begin:end]))
-            begin += 1
-            end += 1
-
-        window_size += 1
-        begin = 0
-        end = window_size
-
-    return max_sum
+    mmax = last = prev = nums[0]
+
+    for i in range(1, len(nums)):
+        prev = nums[i] + last
+        last = max(nums[i], prev)
+        mmax = max(mmax, last)
+
+    return mmax
+
+
+def sum_max_sub_array_accum(nums: list[int]) -> int:
+    accum: list[int] = [nums[0]]
+
+    for i in range(1, len(nums)):
+        prev: int = nums[i] + accum[-1]
+        accum.append(max(nums[i], prev))
+
+    return max(accum)
+
+
+def accum_sub_array_maxes(nums: list[int]) -> list[int]:
+    accum: list[int] = [nums[0]]
+
+    for i in range(1, len(nums)):
+        prev: int = nums[i] + accum[-1]
+        accum.append(max(nums[i], prev))
+
+    return accum

leetcode/test_stuff.py

@@ -1,3 +1,5 @@
+import json
+
 import pytest
 
 import stuff
@@ -465,7 +467,11 @@ def test_trie_busy():
             [-2, 1],
             1,
         ),
+        (
+            json.load(open(".testdata/max_sub_array0.json")),
+            11081,
+        ),
     ],
 )
-def test_maximum_subarray(nums: list[int], expected: int):
+def test_max_sub_array(nums: list[int], expected: int):
     assert stuff.sum_max_sub_array(nums) == expected