Maximum Subarray in Python

Suppose we have an integer array A. We have to find the contiguous subarrays which length will be at least one, and that has the largest sum, and also return its sum. So if the array A is like A = [-2,1,-3,4,-1,2,1,-5,4], then the sum will be 6. And the subarray will be [4, -1, 2, 1]

To solve this we will try to use the Dynamic programming approach.

• define an array dp same as the size of A, and fill it with 0
• dp[0] := A[0]
• for i = 1 to the size of A – 1
  • dp[i] := maximum of dp[i – 1] + A[i] and A[i]
• return max in dp

Let us see the following implementation to get a better understanding −

Example (Python)

 Live Demo

class Solution(object):
   def maxSubArray(self, nums):
      """
      :type nums: List[int]
      :rtype: int
      """
      dp = [0 for i in range(len(nums))]
      dp[0] = nums[0]
      for i in range(1,len(nums)):
         dp[i] = max(dp[i-1]+nums[i],nums[i])
      #print(dp)
      return max(dp)
nums = [-2,1,-3,7,-2,2,1,-5,4]
ob1 = Solution()
print(ob1.maxSubArray(nums))

Input

nums = [-2,1,-3,7,-2,2,1,-5,4]

Output

8

Arnab Chakraborty

Updated on 28-Apr-2020 16:01:53

• Related Questions & Answers
• Maximum Product Subarray in Python
• Program to find maximum subarray min-product in Python
• Maximum Sum Circular Subarray in C++
• Maximum Average Subarray I in C++
• Maximum sum bitonic subarray in C++
• Maximum Average Subarray II in C++
• Program to find maximum ascending subarray sum using Python
• Program to find maximum product of contiguous subarray in Python
• Maximum subarray sum modulo m in C++
• Maximum circular subarray sum in C++\n
• Maximum contiguous sum of subarray in JavaScript
• Python – Sort Matrix by K Sized Subarray Maximum Sum
• Program to find maximum absolute sum of any subarray in Python
• Program to find maximum score of a good subarray in Python
• Program to find maximum length of subarray with positive product in Python