minte9

learningjourney

Binary search (A)

 
# Binary search
#
# You start in the middle of the list, ...
# then you search the second half.

import os

words = []
file = os.path.dirname(__file__) + "/words.txt"
for line in open(file):
    word = line.strip()
    words.append(word)


def full_search(words, keyword):
    i = 0
    for word in words:
        i = i + 1
        if (word == keyword):
            return i
    return i

def binary_search(words, keyword, i=0):
    i = i + 1
    key = len(words) // 2

    if words[key] == keyword:
        return i
   
    if keyword < words[key]: #Look Here
        words = words[:key]
    else:
        words = words[key+1:]
    
    i = binary_search(words, keyword, i)
    return i


print(len(words)) # 113783
print(full_search(words, "mother")) # 62889
print(binary_search(words, "mother")) # 16

Caesar cypher

 
# A Caesar cypher is a weak form on encryption:
# It involves "rotating" each letter by a number (shift it through the alphabet)
#
# Example:
# A rotated by 3 is D; Z rotated by 1 is A
# In a SF movie the computer is called HAL, which is IBM rotated by -1
#
# Our function rotate_word() uses:
#   ord (char to code_number)
#   chr (code to char)

def encrypt(word, no):
    rotated = ""
    for i in range(len(word)):
        j = ord(word[i]) + no
        rotated = rotated + chr(j)
    return rotated

def decrypt(word, no):
    return encrypt(word, -no)

assert encrypt("abc", 3) == "def" # pass
assert encrypt("IBM", -1) == "HAL" # pass

assert decrypt("def", 3) == "abc" # pass
assert decrypt("HAL", -1) == "IBM" # pass

Double letters

 
# Get the words with three consecutive double letters

import os

def has_three_doubles(word):
    i = 0
    jj = 0
    while i < len(word) -1:
        if word[i] == word[i+1]:
            jj = jj + 1
            if jj == 3:
                return True
            i = i + 2
        else:
            jj = 0
            i = i + 1
    return False

assert has_three_doubles("aabbcc") == True
assert has_three_doubles("Mississippi") == False

file = os.path.dirname(__file__) + "/words.txt"
for line in open(file):
    word = line.strip()
    if has_three_doubles(word):
        print(word)
        
        # bookkeeper
        # bookkeepers
        # bookkeeping
        # bookkeepings