HDU 2594 Simpsons’ Hidden Talents KMP的next数组应用

题意：找到最长的s1的前缀=s2的后缀。

把俩字符串连在一起就跟POJ 2752差不多了，不过得判断下长度。

代码：

/*
*  Author:      illuz <iilluzen[at]gmail.com>
*  Blog:        http://blog.youkuaiyun.com/hcbbt
*  File:        hdu2594.cpp
*  Create Date: 2013-11-28 14:50:47
*  Descripton:  kmp 
*/

#include <cstdio>
#include <cstring>

const int MAXN = 5e5 + 1;

char P[MAXN * 2], s1[MAXN], s2[MAXN];
int f[MAXN * 2];

void getVal(char* p, int l) {
	int i = 0, j = -1;
	f[0] = -1;
	while (i < l) {
		if (j == -1 || p[i] == p[j]) {
			i++; j++;
			f[i] = j;
		} else j = f[j];
	}
}

int main() {
	while (~scanf("%s%s", s1, s2)) {
		strcpy(P, s1);
		strcat(P, s2);
		int l1 = strlen(s1), l2 = strlen(s2), l = strlen(P);
		getVal(P, l);
		if (f[l] <= 0) puts("0");
		else if (f[l] > l1 || f[l] > l2) {
			if (l1 > l2)
				printf("%s %d\n", s2, l2);
			else
				printf("%s %d\n", s1, l1);
		} else {
			P[f[l]] = 0;
			printf("%s %d\n", P, f[l]);
		}
	}
	return 0;
}