Computer >> Computer tutorials >  >> Programming >> Python

Array Partition I in Python

Suppose we have an array of 2n number of integers, we have to group these integers into n pairs of integer, like (a1, b1), (a2, b2), ..., (an, bn) which makes sum of min(ai, bi) for all i in range 1 to n as large as possible. So if the input is [1, 4, 3, 2], then output will be 4. So n is 2. And the maximum sum of pairs is 4. This is min(1, 2) + min(3, 4) = 4

To solve this, we will follow these steps −

  • let n is the size of the array
  • sort the array
  • answer := 0
  • for i in range 0 to n, jump by 2
    • answer := answer + array[i]
  • return answer

Example

Let us see the following implementation to get better understanding −

class Solution(object):
   def arrayPairSum(self, a):
      """
      :type nums: List[int]
      :rtype: int
      """
      n = len(a)
      a.sort()
      ans = 0
      for i in range(0,n,2):
         ans += a[i]
      return ans
ob1 = Solution()
print(ob1.arrayPairSum([1,4,3,2]))

Input

[1,4,3,2]

Output

4