What is the time complexity of LeetCode 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum?

The Python solution on this page runs in O(n).

What is the space complexity of LeetCode 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum?

The Python solution on this page uses O(n), where n is the length of the array auxiliary space.

Find Two Non-overlapping Sub-arrays Each With Target Sum — LeetCode 1477 Python Solution

MediumArrayHash TableBinary SearchDynamic ProgrammingSliding Window

Problem: #1477
Pattern: Sliding Window
Reading time: 3 min
Source: leetcode.com

The problem

You are given an array of integers arr and an integer target. You have to find two non-overlapping sub-arrays of arr each with a sum equal target.

Example

Input: arr = [3,2,2,4,3], target = 3
Output: 2
Explanation: Only two sub-arrays have sum = 3 ([3] and [3]). The sum of their lengths is 2.

Python solution

Python

class Solution:
    def minSumOfLengths(self, arr: List[int], target: int) -> int:
        d = {0: 0}
        s, n = 0, len(arr)
        f = [inf] * (n + 1)
        ans = inf
        for i, v in enumerate(arr, 1):
            s += v
            f[i] = f[i - 1]
            if s - target in d:
                j = d[s - target]
                f[i] = min(f[i], i - j)
                ans = min(ans, f[j] + i - j)
            d[s] = i
        return -1 if ans > n else ans

Complexity

Measure	Complexity
Time	O(n)
Space	O(n), where n is the length of the array auxiliary

Pattern: Sliding Window

Collapse a nested loop over every subarray into a single pass with two indices. LeetCode 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum is filed here because LeetCode tags it Sliding Window, which is the vocabulary this hub collects.

The sliding window guide has the Python template for the pattern and the 116 LeetCode problems that use it.

Frequently asked questions

How hard is LeetCode 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum?: LeetCode 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum is rated Medium on LeetCode.
What is the time complexity of LeetCode 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum?: The Python solution on this page runs in O(n).
What is the space complexity of LeetCode 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum?: The Python solution on this page uses O(n), where n is the length of the array auxiliary space.
What topics does LeetCode 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum cover?: LeetCode 1477. Find Two Non-overlapping Sub-arrays Each With Target Sum is tagged Array, Hash Table, Binary Search, Dynamic Programming and Sliding Window on LeetCode.