A + B for you again

#include <stdio.h>
#include <string.h>
char a[100005],b[100005];
int next[100005];
void getnext(int n,char *s)
{
    int i = 0,k = -1;
    next[i] = -1;
    while(i < n)
    {
        if(k == -1 || s[k] == s[i])
        {
            next[++ i] = ++k;
        }
        else k = next[k];
    }
}
int kmp(char *p,char *q)
{
    int n = strlen(p),m = strlen(q);
    getnext(m,q);
    int i = -1,k = -1;
    while(i < n)
    {
        if(k == -1 || p[i] == q[k])
        {
            i ++;
            k ++;
        }
        else k = next[k];
    }
    return k;
}
int main()
{
    while(~scanf("%s%s",a,b))
    {
        int d = kmp(a,b),e = kmp(b,a);//保存a后缀和b前缀的最大重叠 以及 反过来 比较哪个大 就重叠那个 按相应顺序输出，如果相等就按字典序
        if(d > e)printf("%s%s",a,b+d);
        else if(d < e)printf("%s%s",b,a+e);
        else
        {
            if(strcmp(a,b) > 0)printf("%s%s",b,a+e);
            else printf("%s%s",a,b+d);
        }
        putchar(‘\n‘);
    }
}