hdu 1867 A + B for you again

原题链接：http://acm.hdu.edu.cn/showproblem.php?pid=1867
kmp。。。

注意: 字符串A+B也可是B+A反正输出相加之后最短的那个，若相加之后长度相等输出字典序最小的那个。。

#include<algorithm>#include<iostream>#include<cstdlib>#include<cstring>#include<cstdio>#include<vector>#include<map>using std::cin;using std::cout;using std::endl;using std::find;using std::sort;using std::map;using std::pair;using std::vector;using std::multimap;#define pb(e) push_back(e)#define sz(c) (int)(c).size()#define mp(a, b) make_pair(a, b)#define all(c) (c).begin(), (c).end()#define iter(c) decltype((c).begin())#define cls(arr,val) memset(arr,val,sizeof(arr))#define cpresent(c, e) (find(all(c), (e)) != (c).end())#define rep(i, n) for (int i = 0; i < (int)(n); i++)#define tr(c, i) for (iter(c) i = (c).begin(); i != (c).end(); ++i)const int N = 100010;typedef unsigned long long ull;int next[N];char str1[N], str2[N];struct KMP {    int i, j, n, m;    inline void get_next(char *src) {        m = strlen(src);        for (i = 1, j = next[0] = 0; i < m; i++) {            while (j > 0 && src[i] != src[j]) j = next[j - 1];            if (src[i] == src[j]) j++;            next[i] = j;        }    }    inline int kmp_match(char *text, char *pat) {        n = strlen(text);        for (i = j = 0; i < n; i++) {            while (j > 0 && text[i] != pat[j]) j = next[j - 1];            if (text[i] == pat[j]) j++;        }        return j;    }}go;int main() {#ifdef LOCAL    freopen("in.txt", "r", stdin);    freopen("out.txt", "w+", stdout);#endif    int p, q;    while (~scanf("%s %s", str1, str2)) {        go.get_next(str2);        p = go.kmp_match(str1, str2);        go.get_next(str1);        q = go.kmp_match(str2, str1);        if (p > q || (p == q && -1 == strcmp(str1, str2))) {            printf("%s%s\n", str1, str2 + p);        } else {            printf("%s%s\n", str2, str1 + q);        }    }    return 0;}