Description 1942
The coding system works like this:
• The words are arranged in the increasing order of their length.
• The words with the same length are arranged in lexicographical order (the order from the dictionary).
• We codify these words by their numbering, starting with a, as follows:
a - 1
b - 2
...
z - 26
ab - 27
...
az - 51
bc - 52
...
vwxyz - 83681
...
Specify for a given word if it can be codified according to this coding system. For the affirmative case specify its code.
Input
• The word is maximum 10 letters length
• The English alphabet has 26 characters.
Output
Sample Input
bf
Sample Output
55 1496
Description
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 will be terminated by end-of-file.
Output
Sample Input
z
a
cat
vwxyz
Sample Output
26
1
0
83681
#include"iostream"
#include"cstdio"
#include"cstring"
using namespace std;
const int ms=;
int c[ms+][ms+];
int main()
{
int i,j;
//bool flag;
for(i=;i<=ms;i++)
{
c[i][]=c[i][i]=;
}
for(i=;i<=ms;i++)
for(j=;j<i;j++)
c[i][j]=c[i-][j]+c[i-][j-];
char str[ms];
while(scanf("%s",str)!=EOF)
{
bool flag=false;
int len=strlen(str);
for(i=;i<len;i++)
if(str[i]<=str[i-])
{
flag=true;
break;
}
if(flag)
{
printf("0\n");
continue;
}
int ans=;
i=;
while(i<len)
ans+=c[][i++];
i=-;
int k=;
while(k<len)
{
i++;
if(k==len-)
{
//if(i+'a'<=str[k])
while(i+'a'<=str[k])
{
ans++;
i++;
}
break;
}
while(i+'a'<str[k])
{
//if(i+'a'<str[k])
//{
ans+=c[-i-][len--k];
i++;
continue; }
k++;
}
printf("%d\n",ans);
}
return ;
}