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1995 East-Central Regionals
ACM International Collegiate programming Contest
sponsored by Microsoft
Problem F - Word Index
Encoding schemes are often used in situations requiring encryption or information storage/transmission
economy. Here, we develop a simple encoding scheme that encodes particular types of words with five or
fewer (lower case) letters as integers.
Consider the English alphabet {a,b,c,...z}. Using this alphabet, a set of valid words are to be formed that
are in a strict lexicographic order. In this set of valid words, the successive letters of a word are in a strictly
ascending order; that is, later letters in a valid word are always after previous letters with respect to their
positions in the alphabet list {a,b,c...,z}. For example,
abc aep gwz
are all valid three-letter words, whereas
aab are cat
are not.
For each valid word associate an integer which gives
the position of the word in the alphabetized list of
words. That is:
a --> 1
b --> 2
.
.
z --> 26
ab --> 27
ac --> 28
.
.
az --> 51
bc --> 52
.
.
vwxyz --> 83681
Your program is to read a series of input lines. Each input line will have a single word on it, that will be
from one to five letters long. For each word read, if the word is invalid give the number 0. If the word read
is valid, give the word's position index in the above alphabetical list.
Input
The input consists of a series of single words, one per line. The words are at least one letter long and no
more that five letters. Only the lower case alphabetic {a,b,...,z} characters will be used as input. The first
letter of a word will appear as the first character on an input line.
The input will be terminated by end-of-file.
Output
The output is a single integer, greater than or equal to zero (0) and less than or equal 83681. The first digit
of an output value should be the first character on a line. Note: This may not be a default-format. There is
one line of output for each input line.
Sample Input
z
a
cat
vwxyz
Output for the Sample Input
26
1
0
83681
Last updated November 6, 1997