Created
December 17, 2019 12:56
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# | |
# 対話モード >>> に | |
# コピペで実行できます。 | |
# | |
import bisect | |
import random | |
import timeit | |
# | |
# 1. 関数を定義 | |
# | |
def index(a, x): | |
'Locate the leftmost value exactly equal to x' | |
i = bisect.bisect_left(a, x) | |
if i != len(a) and a[i] == x: | |
return i | |
raise ValueError | |
# | |
# 2. N + 1 個のランダムな数をソートしたリスト | |
# | |
N = 10**3 | |
lst = sorted( | |
random.randint(0, N) for _ in range(N + 1)) | |
# | |
# 3. 検索対象の値を選定 | |
# | |
Q = N // 4 # Quoter の Q | |
value0 = lst[0 * Q] # 先頭 | |
value1 = lst[1 * Q] | |
value2 = lst[2 * Q] # 真ん中 | |
value3 = lst[3 * Q] | |
value4 = lst[4 * Q] # 末尾 | |
# N + '1' 個にしてるのは | |
# こんな感じに分割できるから | |
# 0, 1, 2, 3, 4, 5, 6, 7, 8 | |
# x x x x x | |
# | |
# 4. 計測 | |
# | |
timeit.timeit('lst.index(value0)', globals=globals()) | |
timeit.timeit('lst.index(value1)', globals=globals()) | |
timeit.timeit('lst.index(value2)', globals=globals()) | |
timeit.timeit('lst.index(value3)', globals=globals()) | |
timeit.timeit('lst.index(value4)', globals=globals()) | |
timeit.timeit('index(lst, value0)', globals=globals()) | |
timeit.timeit('index(lst, value1)', globals=globals()) | |
timeit.timeit('index(lst, value2)', globals=globals()) | |
timeit.timeit('index(lst, value3)', globals=globals()) | |
timeit.timeit('index(lst, value4)', globals=globals()) |
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