hdu 2954 Simpsons’ Hidden Talents(KMP)

题目链接：hdu 2954 Simpsons’ Hidden Talents

题目大意：给出两个字符串，找出一个子串，为s1的前缀，s2的后缀， 要求子串最长，并且输出该子串。

解题思路：将s1和s2首尾相连，然后求出next数组的next[n+m]的位置，然后和n、m取最小值即为答案。

#include <stdio.h>
#include <string.h>
#define min(a,b) (a)<(b)?(a):(b)

const int N = 1e5+5;

int n, m, next[N];
char s1[N], s2[N];

void getNext () {
	int p = 0;
	m = strlen(s1+1);
	for (int i = 2; i <= m; i++) {
		while (p > 0 && s1[p+1] != s1[i])
			p = next[p];

		if (s1[p+1] == s1[i])
			p++;

		next[i] = p;
	}
}

int main () {
	while (scanf("%s%s", s1+1, s2+1) == 2) {
		n = min (strlen(s1+1), strlen(s2+1));
		strcat (s1+1, s2+1);

		getNext ();

		int ans = min (next[m], n);
		for (int i = 1; i <= ans; i++) printf("%c", s1[i]);
		if (ans) printf(" ");
		printf("%d\n", ans);
	}
	return 0;
}

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hdu 2954 Simpsons’ Hidden Talents(KMP)

原文：http://blog.csdn.net/keshuai19940722/article/details/21483799