Syntax error Program to check number of triplets from an array whose sum is less than target or not Python

Program to check number of triplets from an array whose sum is less than target or not Python

Suppose we have a list of numbers called nums and another value target, we have to find the number of triples (i < j < k) that exist such that nums[i] + nums[j] + nums[k] < target.

So, if the input is like nums = [−2, 6, 4, 3, 8], target = 12, then the output will be 5, as the triplets are: [−2,6,4], [−2,6,3], [−2,4,3], [−2,4,8], [−2,3,8]

To solve this, we will follow these steps −

  • sort the list nums

  • ans := 0

  • n := size of nums

  • for i in range 0 to n−1, do

    • k := n − 1

    • for j in range i + 1 to n−1, do

      • while k > j and nums[i] + nums[k] + nums[j] >= target, do

        • k := k − 1

      • if j is same as k, then

    • ans := ans + k − j

  • return ans

Let us see the following implementation to get better understanding −

Example

 Live Demo

class Solution:
   def solve(self, nums, target):
      nums.sort()
      ans = 0
      n = len(nums)
      for i in range(n):
         k = n − 1
         for j in range(i + 1, n):
            while k > j and nums[i] + nums[k] + nums[j] >=
target:
               k -= 1
            if j == k:
               break
            ans += k − j
      return ans
ob1 = Solution()
nums = [−2, 6, 4, 3, 8]
target = 12
print(ob1.solve(nums, target))

Input

[-2, 6, 4, 3, 8], 12

Output

5
Updated on: 2020-10-21T11:40:48+05:30

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