Given the mapping a = 1, b = 2, ... z = 26, and an encoded message, count the number of ways it can be decoded.

Daily_coding_Problem_7.py

'''
For example, the message '111' would give 3, since it could be decoded as 'aaa', 'ka', and 'ak'.
'''
def decode_msg(msg):
    n=len(msg)
    if n==0 or msg=='0' or msg[0]=='0':
        return 0
    n=len(msg)
    count=[0]*(n+1)  
    count[0]=1
    count[1]=1
    for i in range(2,n+1): 
        count[i] = 0
        if(msg[i-1] > '0'): 
            count[i]=count[i-1] 
        if(msg[i-2]=='1' or (msg[i-2]=='2' and msg[i-1] < '7') ): 
            count[i]+=count[i-2]
    return count[n]