import bisect

# 已知一個有序序列
ordered_list = [23, 34, 59, 78, 99]

des_element = 21
res = bisect.bisect(ordered_list, des_element)
print(res) # res: 0

des_element = 35
res = bisect.bisect(ordered_list, des_element)
print(res) # res: 2

import bisect

# 已知一個有序序列
ordered_list = [23, 34, 34, 59, 78, 99]

# bisect函數(shù)默認返回右側(cè)的位置索引
des_element = 34
res = bisect.bisect(ordered_list, des_element)
print(res) # res: 3

# bisect函數(shù)為bisect_right函數(shù)的別名
des_element = 34
res = bisect.bisect_right(ordered_list, des_element)
print(res) # res: 3

# bisect_left函數(shù)默認返回左側(cè)的位置索引
des_element = 34
res = bisect.bisect_left(ordered_list, des_element)
print(res) # res: 1

'''
  考試成績的檔位劃分，共分為5個等級：
    1. F等級：[0, 60)
    2. D等級：[60, 70)
    3. C等級：[70, 80)
    4. B等級：[80, 90)
    5. A等級：[90, 100]
'''

import bisect


def get_result(score: (int, float), score_nodes: list = [60, 70, 80, 90], ranks='FDCBA') -> str:

  # 校驗：分數(shù)范圍
  if score < 0 or score >100:
    return "score的取值范圍：0-100"

  # 邊界點考慮
  if int(score) == 100:
    return "A"

  loc_index = bisect.bisect(score_nodes, score)
  return ranks[loc_index]

print(get_result(50))    # res: F
print(get_result(60))    # res: D
print(get_result(85.5))   # res: B
print(get_result(100))   # res: A