ZOJ1009 Enigma-优快云博客

本文介绍了一个基于Enigma机器原理的解密算法实现。通过使用C++编程语言，该程序能够模拟Enigma机器的密码转子操作，实现对输入密文的解密过程。程序包括密码表初始化、轮转表更新及解密核心逻辑等功能。

#include<iostream>
#include<string>
usingnamespacestd;

introtor[3][26];//密码表
intrround[3];//加权轮转表
inttotalLetter;

voidnextStep()
{//密码表轮转
rround[0]++;
if(rround[0]%totalLetter==0)
{
rround[1]++;
rround[0]=0;
if(rround[1]%totalLetter==0)
{
rround[2]++;
rround[2]%=totalLetter;
rround[1]=0;
}
}
}

voidrevolve(charch)
{//利用密码表解密
intnum,i;
num=ch-'A';
for(i=2;i>=0;i--)
{
num+=rotor[i][(num-rround[i]+totalLetter)%totalLetter];
num=(num+totalLetter)%totalLetter;
}
cout<<(char)('a'+num);
}

intmain()
{
stringcurLine;
inti,j,nCase;
intnumCrypt;
nCase=1;
while(cin>>totalLetter&&totalLetter!=0)
{
memset(rotor,0,sizeof(rotor));//密码表清零
//初始化密码表
for(i=0;i<3;i++)
{
cin>>curLine;
for(j=0;j<totalLetter;++j)
{
rotor[i][curLine[j]-'A']=j-(curLine[j]-'A');
}
}
if(nCase!=1)
cout<<endl;
cin>>numCrypt;
cout<<"Enigma"<<nCase++<<":"<<endl;
for(i=0;i<numCrypt;i++)
{
memset(rround,0,sizeof(rround));//加权轮转表清零
j=0;
cin>>curLine;//输入密文
while(curLine[j]!='/0')
{
revolve(curLine[j++]);//解密
nextStep();//密码表轮转
}
cout<<endl;
}
}
return0;
}