杭电1048

心已赠人 2022-09-17 03:04 172阅读 0赞

# The Hardest Problem Ever #

**Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/32768 K (Java/Others)  
Total Submission(s): 13447 Accepted Submission(s): 6123**

Problem Description

Julius Caesar lived in a time of danger and intrigue. The hardest situation Caesar ever faced was keeping himself alive. In order for him to survive, he decided to create one of the first ciphers. This cipher was so incredibly sound, that no one could figure it out without knowing how it worked.  
You are a sub captain of Caesar's army. It is your job to decipher the messages sent by Caesar and provide to your general. The code is simple. For each letter in a plaintext message, you shift it five places to the right to create the secure message (i.e., if the letter is 'A', the cipher text would be 'F'). Since you are creating plain text out of Caesar's messages, you will do the opposite:  
  
Cipher text  
A B C D E F G H I J K L M N O P Q R S T U V W X Y Z  
  
Plain text  
V W X Y Z A B C D E F G H I J K L M N O P Q R S T U  
  
Only letters are shifted in this cipher. Any non-alphabetical character should remain the same, and all alphabetical characters will be upper case.

Input

Input to this problem will consist of a (non-empty) series of up to 100 data sets. Each data set will be formatted according to the following description, and there will be no blank lines separating data sets. All characters will be uppercase.  
  
A single data set has 3 components:  
  
Start line - A single line, "START"  
  
Cipher message - A single line containing from one to two hundred characters, inclusive, comprising a single message from Caesar  
  
End line - A single line, "END"  
  
Following the final data set will be a single line, "ENDOFINPUT".

Output

For each data set, there will be exactly one line of output. This is the original message by Caesar.

Sample Input

START
    NS BFW, JAJSYX TK NRUTWYFSHJ FWJ YMJ WJXZQY TK YWNANFQ HFZXJX
    END
    START
    N BTZQI WFYMJW GJ KNWXY NS F QNYYQJ NGJWNFS ANQQFLJ YMFS XJHTSI NS WTRJ
    END
    START
    IFSLJW PSTBX KZQQ BJQQ YMFY HFJXFW NX RTWJ IFSLJWTZX YMFS MJ
    END
    ENDOFINPUT

Sample Output

IN WAR, EVENTS OF IMPORTANCE ARE THE RESULT OF TRIVIAL CAUSES
    I WOULD RATHER BE FIRST IN A LITTLE IBERIAN VILLAGE THAN SECOND IN ROME
    DANGER KNOWS FULL WELL THAT CAESAR IS MORE DANGEROUS THAN HE

代码如下：

#include <iostream>
    #include <string>
    using namespace std;
    
    inline bool isUpperAlpha(char ch)
    {
    	return (ch >= 'A' && ch <= 'Z') ;
    	return false ;
    }
    
    void deCipher(string& mesg)
    {
    	for (int i = 0 ; i < mesg.length(); ++ i)
    		if (isUpperAlpha(mesg[i]))
    			mesg[i] = ((mesg[i] - 'A' )+ 26 - 5) % 26 + 'A';
    	cout << mesg << endl;
    }
    
    void process()
    {
    	string start, mesg ,end;
    	while (getline(cin, start))
    	{
    		if (start == "ENDOFINPUT" || start != "START") break ;
    		getline(cin, mesg);
    		deCipher(mesg) ;
    		getline(cin, end) ;
    	}
    }
    
    int main(int argc, char** argv)
    {
    	process() ;
    	return 0 ;
    }