hysteresis.py

series = [
    10,
    57,
    33,
    21,
    19,
    20,
    18,
    17,
    24,
    89,
    21,
    22,
    22,
    22,
    23,
    27,
    29,
    30,
    30,
    31,
    30,
    29,
    30,
    31,
    32,
    18, #####
    33,
    21,
    19,
    20,
    18,
    17,
    24,
    21,
    19,
    20,
    18,
    17,
    24,
    50,
    55,
    56,
    52,
    57,
    49,
    18,
    17,
    24,
    21,
    19,
    19,
]


T1 = 25 # Detect threshold
T2 = 0.75 * T1 # Undetect threshold
M = 6 # At least M minutes we need to have exceeded

##############

processed = []
counter = 0

for t, response_time in enumerate(series):
    if response_time > T1 or response_time > T2:
        counter += 1
    else:
        counter = 0

    processed.append((t, response_time, counter))

highlight = -1

for (t, response_time, counter) in reversed(processed):
    marker = ''

    if counter > M and highlight == -1:
        highlight = counter

    if highlight > 0:
        highlight -= 1
        marker = '<<<<<<<<<<<'

    if highlight == 0:
        highlight = -1

    print(t, '\t', response_time, '\t', counter, '\t', marker)