input: Write a python function to solve the assignment problem using the given cost matrix.
  assert assignmentProblem([[4, 1, 3], [2, 0, 5], [3, 2, 2]]) == [[1, 1], [2, 2]]
  assert assignmentProblem([[82, 83, 69, 92], [77, 37, 49, 92], [11, 69, 5, 86], [8, 9, 98, 23]]) == [[2, 2], [3, 1]]
  assert assignmentProblem([[90, 75, 75, 80], [35, 85, 55, 65], [125, 95, 90, 105], [45, 110, 95, 115]]) == [[0, 1], [3, 0]]
output: def assignmentProblem(cost_matrix):
      from scipy.optimize import linear_sum_assignment
  
      row_ind, col_ind = linear_sum_assignment(cost_matrix)
      return list(zip(row_ind, col_ind))