decode_message.py

"""

Give an file as input which has following data

3 love
6 computers
2 dogs
4 cats
1 I
5 you


Arranging them into a pyramid and picking. the right most numbers 1,3,6 get the values of them from the given input file. 

   1
  2 3  
4  5 6

The expected out here is "I love computers"
"""


def decode_message(file) -> str:
    number_map = dict()
    # prepare a map for number: str
    with open(file) as f:
        for line in f.readlines():
            row = line.split(' ')
            number_map[row[0]] = ' '.join(row[1:]).replace('\n','')
    
    result = []
    for i in range(1,len(number_map.items())+1):
        pyramid_last_value = str(int((i*i+i)/2))
        
        if pyramid_last_value in number_map:
            result.append(number_map[pyramid_last_value])    
        else:
            # We don't have that many numbers to scan
            break
    
    return ' '.join(result)