class Solution:
  def searchTriplets(self, arr, target):
    count = 0
    arr.sort()

    for i in range(len(arr)-2):
      left, right = i + 1, len(arr)-1 # pointers

      while left < right:
        sum_elements = arr[i] + arr[left] + arr[right]
        
        if sum_elements < target: # if it's small then all to the left are valid
          count += (right - left)
          left += 1
        else:
          right -= 1   
          
    return count