from heapq import *

class Solution:
  def findNextInterval(self, intervals):
    
    e_min_heap = []
    s_min_heap = []

    for i in range(len(intervals)):
      s_min_heap.append((intervals[i].start, i))
      e_min_heap.append((intervals[i].end, i))

    heapify(s_min_heap)
    heapify(e_min_heap)  

    result = [-1 for _ in range(len(intervals))]

    while e_min_heap:
      end, end_index = heappop(e_min_heap)

      while s_min_heap:
        start, start_index = heappop(s_min_heap)
        if start_index > end_index and start >= end:
          result[end_index] = start_index
          break
      
    return result