F - The Hardest Problem Ever解题报告

F - The Hardest Problem Ever

Time Limit:1000MS    Memory Limit:32768KB    64bit IO Format:%I64d & %I64u

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 descri_ption, 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

STARTNS BFW, JAJSYX TK NRUTWYFSHJ FWJ YMJ WJXZQY TK YWNANFQ HFZXJXENDSTARTN BTZQI WFYMJW GJ KNWXY NS F QNYYQJ NGJWNFS ANQQFLJ YMFS XJHTSI NS WTRJENDSTARTIFSLJW PSTBX KZQQ BJQQ YMFY HFJXFW NX RTWJ IFSLJWTZX YMFS MJENDENDOFINPUT

 

Sample Output

IN WAR, EVENTS OF IMPORTANCE ARE THE RESULT OF TRIVIAL CAUSESI WOULD RATHER BE FIRST IN A LITTLE IBERIAN VILLAGE THAN SECOND IN ROMEDANGER KNOWS FULL WELL THAT CAESAR IS MORE DANGEROUS THAN HE曾经最难的问题？其实一点都不难。只是对字符进行偏移而已。但是它容易错的地方是必须在读入START 文本 END之后输出结果才是对的，如果在读入文本后就输出结果，就会出错。
//The Hardest Problem Ever#include <stdio.h>#include <string.h>char *Plain(char s[]);void main(){char s[1000];char t[1000];while (1){gets(s);if (strcmp(s,"ENDOFINPUT") == 0)break;else if (strcmp(s,"START") == 0){gets(s);gets(t);printf("%s\n",Plain(s));}}}char *Plain(char s[]){long i;for (i = 0;s[i];i ++){if (s[i] >= 'A' && s[i] <= 'E'){s[i] = 'V' + s[i] - 'A';}else if (s[i] > 'E' && s[i] <= 'Z'){s[i] = 'A' + s[i] - 'F';}}return s;}