LeetCode [1546] Maximum Number of Non-Overlapping Subarrays With Sum Equals Target

 1546. Maximum Number of Non-Overlapping Subarrays With Sum Equals Target

Medium

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.

Example 3:

Input: nums = [-2,6,6,3,5,4,1,2,8], target = 10
Output: 3

Example 4:

Input: nums = [0,0,0], target = 0
Output: 3

 

Constraints:

• 1 <= nums.length <= 10^5
• -10^4 <= nums[i] <= 10^4
• 0 <= target <= 10^6

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class Solution { public int maxNonOverlapping(int[] nums, int target) { Map<Integer, Integer> map = new HashMap<>(); map.put(0, 0); int res = 0; int sum = 0; for (int i = 0; i < nums.length; ++i) { sum += nums[i]; if (map.containsKey(sum - target)) { res = Math.max(res, map.get(sum - target) + 1); } map.put(sum, res); } return res; } }