A. Jabber ID
time limit per test
0.5 second
memory limit per test
256 megabytes
input
standard input
output
standard output
Jabber ID on the national Berland service «Babber» has a form <username>@<hostname>[/resource], where
The content of square brackets is optional — it can be present or can be absent.
There are the samples of correct Jabber IDs: mike@codeforces.com, 007@en.codeforces.com/contest.
Your task is to write program which checks if given string is a correct Jabber ID.
Input
The input contains of a single line. The line has the length between 1 and 100 characters, inclusive. Each characters has ASCII-code between 33 and 127, inclusive.
Output
Print YES or NO.
Examples
input
mike@codeforces.com
output
YES
input
john.smith@codeforces.ru/contest.icpc/12
output
NO
直接模拟
#include<stdio.h>
#include<string.h>
bool panduan(char c)
{
if((c!='_')&&(c<'a'||c>'z')&&(c<'A'||c>'Z')&&(c<'0'||c>'9'))return false;
else return true;
}
int main()
{
char s[100+10];
gets(s);
int len=strlen(s);
char user[100];
char host[100];
char res[100];
int i,len1,len2,len3;
int ans=1;
//user
for(i=0;i<len;i++)
{
if(s[i]=='@')
{
len1=i;
break;
}
user[i]=s[i];
if(i==len-1&&s[i]!='@')ans=0;
}
if(s[len-1]=='@')
ans=0;
if(ans==1)
{
if(len1<1||len1>16)ans=0;
else
{
for(i=0;i<len1;i++)
{
if(!panduan(user[i]))
{
ans=0;
break;
}
}
}
}
//host
for(i=len1+1;i<len;i++)
{
if(s[i]=='/')
{
len2=i-len1-1;
break;
}
host[i-len1-1]=s[i];
if(i==len-1&&s[i]!='/')
{
len2=len-len1-1;
}
}
if(ans==1)
{
if(len1<1||len1>32)ans=0;
else
{
int sum=0;
for(i=0;i<len2;i++)
{
if(!panduan(host[i]))
{
if(host[i]=='.')
{
if(sum>16||sum<1||(i==len2-1))
{
ans=0;break;
}
sum=0;
}
else ans=0;
}
else sum++;
if(ans==0)
break;
}
}
}
//res
if(s[len-1]=='/')
ans=0;
if(len1+len2+2<len&&ans==1)
{
for(i=len1+len2+2;i<len;i++)
res[i-len1-len2-2]=s[i];
len3=len-2-len1-len2;
if(len3<1||len3>16)ans=0;
else{
for(i=0;i<len3;i++)
{
if(!panduan(res[i]))
{
ans=0;
break;
}
}}
}
if(ans==1)printf("YES\n");
else printf("NO\n");
return 0;
}