1546. Maximum Number of Non-Overlapping Subarrays With Sum Equals Target
Description
Given an array nums
and an integer target
, return the maximum number of non-empty non-overlapping subarrays such that the sum of values in each subarray is equal to target
.
Example 1:
Input: nums = [1,1,1,1,1], target = 2 Output: 2 Explanation: There are 2 non-overlapping subarrays [1,1,1,1,1] with sum equals to target(2).
Example 2:
Input: nums = [-1,3,5,1,4,2,-9], target = 6 Output: 2 Explanation: There are 3 subarrays with sum equal to 6. ([5,1], [4,2], [3,5,1,4,2,-9]) but only the first 2 are non-overlapping.
Constraints:
1 <= nums.length <= 105
-104 <= nums[i] <= 104
0 <= target <= 106
Solutions
Solution 1: Greedy + Prefix Sum + Hash Table
We traverse the array $nums$, using the method of prefix sum + hash table, to find subarrays with a sum of $target$. If found, we increment the answer by one, then we set the prefix sum to $0$ and continue to traverse the array $nums$ until the entire array is traversed.
The time complexity is $O(n)$, and the space complexity is $O(n)$. Here, $n$ is the length of the array $nums$.
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