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

Problem Link

Description

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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

Solution

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Python3

class Solution:
    def maxNonOverlapping(self, nums: List[int], target: int) -> int:
        
        d = {0:-1}
        last = -1
        s = res = 0
        
        for i,num in enumerate(nums):
            s += num
            if s - target in d and d[s-target] >= last:
                last = i
                res += 1
            
            d[s] = i
        
        return res