思路就是基于两次xor还原的性质

#include<stdio.h>
#include<string.h>
char space[20100],nospace[20100];
int main()
{
	int len,i;
	char key,clear;
	//freopen("in.txt","r",stdin);
	scanf("%s",nospace);
	scanf("%s",space);
	len=strlen(nospace);
	for(i=0;i<=len-1;i++)
	{
		if (nospace[i]>='0'&&nospace[i]<='9')
			nospace[i]-='0';
		else nospace[i]=nospace[i]-('A'-10);
	}
	for(i=0;i<=len-1+2;i++)
	{
		if (space[i]>='0'&&space[i]<='9')
			space[i]-='0';
		else space[i]=space[i]-('A'-10);
	}
	len/=2;
	for(i=0;i<=len-1;i++)
		nospace[i]=nospace[i*2]*16+nospace[i*2+1];
	for(i=0;i<=len;i++)
		space[i]=space[i*2]*16+space[i*2+1];
	clear=' ';
	for(i=0;i<=len-1;i++)
	{
		key=space[i]^clear;
		clear=nospace[i]^key;
		printf("%02X",key);
	}
	key=space[i]^clear;
	printf("%02X\n",key);
	return 0;
}

• 经验问题…… (822) 00448264 2006-01-13 17:33:32
  • 多谢指教，郁闷了几个小时 (900) gamme 2006-01-13 17:41:04
  • Re:经验问题…… (900) bailu1234 2008-06-22 12:23:07
• Re:请高手帮我看一下WA的原因啊，多谢了 (64) tekkie 2008-07-08 23:31:08