coinflips.py

import random
from copy import copy

def ishead():
    result=random.uniform(0,1)
    if result>=0.5:
        return 1
    else:
        return 0

def generateseq(seq_length=20):
    seq_of_flips=[]
    for i in range(seq_length):
        seq_of_flips.append(ishead())

    return seq_of_flips

def find_sequences_in_data(data):
    """
    Find the sequences in a list of data

    :return: list of sequences
    """
    data_left = copy(data)
    sequences_found = []

    while len(data_left)>0:
        if len(data_left)==1:
            sequences_found.append([data_left[0]])
            return sequences_found

        offset=0
        in_sequence = True
        this_sequence = []
        while in_sequence:
            this_sequence.append(data_left[offset])
            if offset==(len(data_left)-1):
                # end of the line
                break
            if data_left[offset]!=data_left[offset+1]:
                # out of sequence
                break
            offset = offset+1

        sequences_found.append(this_sequence)
        data_left = data_left[offset+1:]

    return sequences_found

def longest_sequence_of_heads(sequences_found):
    longest_length = 0
    for seq in sequences_found:
        if all(x == 1 for x in seq):
            # all heads
            len_heads = len(seq)
            if len_heads>longest_length:
                longest_length = len_heads
    return longest_length

def atleastnheadsinseq(min_heads=5, seq_length=20):
    flips_data = generateseq(seq_length)
    sequences_found = find_sequences_in_data(flips_data)
    length_of_longest_run_of_heads = longest_sequence_of_heads(sequences_found)

    if length_of_longest_run_of_heads>=min_heads:
        return 1
    else:
        return 0

count_min_heads=[]
# start with small values to begin with
for i in range(1000000):
    result = atleastnheadsinseq()
    count_min_heads.append(result)

print(sum(count_min_heads)/len(count_min_heads))