hdu 1867 A + B for you again

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asdf ghjk

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#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int  MAXN= 100010;
char s1[MAXN],s2[MAXN];
int next[MAXN];
void get_nextval(char s[])//求next数组
{
int i,j;
i = -1;
j = 0;
next[0] = -1;
int len = strlen(s);
while(j<len)
{
if(i == -1 || s[i] == s[j])
{
j++; i++;
next[j] = i;
}
else
i = next[i];
}
}

int KMP(char s1[],char s2[])//返回s1后缀和s2前缀的最大相同长度！！！！！，参数的顺序很重要。
{
int i,j;
i = 0;
j = 0;
get_nextval(s2);
int len1 = strlen(s1),len2 = strlen(s2);
while(i<len1 && j<len2)
{
if(j == -1 || s1[i] == s2[j])
{
i++; j++;
}
else
j = next[j];
}
//kmp改进部分
if(i == len1)
{
return j;
}
return 0;
}

int main()
{
int a,b;
while(scanf("%s%s",s1,s2) != EOF)
{
a = KMP(s1,s2);
b = KMP(s2,s1);//首先取最短的字符串输出，如果相同，比较字典序即可
if(a == b)
{
if(strcmp(s1,s2)>0)
printf("%s%s\n",s2,s1+a);
else
printf("%s%s\n",s1,s2+a);//s2+a意思是从s2[a]开始输出字符串
}
else if(a>b)
{
printf("%s%s\n",s1,s2+a);
}
else
printf("%s%s\n",s2,s1+b);
}
return 0;
}