Documentation Index
Fetch the complete documentation index at: /llms.txt
Use this file to discover all available pages before exploring further.
Tested Python solution for LeetCode 325 with 15 pytest cases. Generate a practice environment with lcpy.
lcpy gen -n 325 # by problem number
lcpy gen -s maximum_size_subarray_sum_equals_k # by problem name
nums and an integer k, return the maximum length of a subarray that sums to k. If there is not one, return 0 instead.
Input: nums = [1,-1,5,-2,3], k = 3
Output: 4
Explanation: The subarray [1, -1, 5, -2] sums to 3 and is the longest.
Input: nums = [-2,-1,2,1], k = 1
Output: 2
Explanation: The subarray [-1, 2] sums to 1 and is the longest.
1 <= nums.length <= 2 * 10^5-10^4 <= nums[i] <= 10^4-10^9 <= k <= 10^9class Solution:
# Time: O(n) — single pass, O(1) hash lookups
# Space: O(n) — first-occurrence index per prefix sum
def max_sub_array_len(self, nums: list[int], k: int) -> int:
first_index = {0: -1}
prefix_sum = 0
best = 0
for i, num in enumerate(nums):
prefix_sum += num
if prefix_sum - k in first_index:
best = max(best, i - first_index[prefix_sum - k])
if prefix_sum not in first_index:
first_index[prefix_sum] = i
return best
| Time | Space |
|---|---|
| O(n) — single pass, O(1) hash lookups | O(n) — first-occurrence index per prefix sum |