HDU - 4511 小明系列故事――女友的考验(AC自动机+DP)

 3 1
1 1
2 1
3 1
2
1 2

2 1
0 0
1 1
2 
1 2

5 3
0 0
5 3
1 2
1 22
5 21
3
1 2 3
2 
4 5
2
1 5

0 0 

 2.00
Can not be reached!
21.65 

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cstdlib>
#include <set>
#include <queue>
#include <cmath>
using namespace std;
const double inf = 1e20;

pair<int, int> p[100];
int n;
double dp[55][1000];

double dis(pair<int, int> a, pair<int, int> b) {
	  return sqrt((double)(1.0 * a.first - b.first) * (1.0 * a.first - b.first) + (double)(1.0 * a.second - b.second)*(1.0 * a.second - b.second));
}

struct Tie {
	int nxt[1000][55], fail[1000], end[1000];
	int root, cnt;

	int newNode() {
		for (int i = 1; i <= n; i++) 
			nxt[cnt][i] = -1;
		end[cnt++] = 0;
		return cnt - 1;
	}

	void init() {
		cnt = 0;
		root = newNode();
	}

	void insert(int a[], int len) {
		int now = root;
		for (int i = 0; i < len; i++) {
			if (nxt[now][a[i]] == -1)
				nxt[now][a[i]] = newNode();
			now = nxt[now][a[i]];
		}
		end[now] = 1;
	}

	void build() {
		queue<int> q;
		fail[root] = root;
		for (int i = 1; i <= n; i++) {
			if (nxt[root][i] == -1)
				nxt[root][i] = root;
			else {
				fail[nxt[root][i]] = root;
				q.push(nxt[root][i]);
			}
		}

		while (!q.empty()) {
			int now = q.front();
			q.pop();
			end[now] |= end[fail[now]];
			for (int i = 1; i <= n; i++) {
				if (nxt[now][i] == -1)
					nxt[now][i] = nxt[fail[now]][i];
				else {
					fail[nxt[now][i]] = nxt[fail[now]][i];
					q.push(nxt[now][i]);
				}
			}
		}
	}

	void solve() {
		for (int i = 1; i <= n; i++)
			for (int j = 0; j < cnt; j++)
				dp[i][j] = inf;
		dp[1][nxt[root][1]] = 0;
		for (int i = 1; i < n; i++) 
			for (int j = 0; j < cnt; j++) 
				if (dp[i][j] < inf) {
					for (int k = i+1; k <= n; k++) {
						int cur = nxt[j][k];
						if (end[cur]) continue;
						dp[k][cur] = min(dp[k][cur], dp[i][j] + dis(p[i], p[k]));
					}
				}

		double ans = inf;
		for (int i = 0; i < cnt; i++) 
			if (dp[n][i] < inf) 
				ans = min(ans, dp[n][i]);

		if (ans == inf) 
			printf("Can not be reached!\n");
		else printf("%.2lf\n", ans);
	}
} ac;

int a[10];

int main() {
	int m;
	while (scanf("%d%d", &n, &m) != EOF && n + m) {
		for (int i = 1; i <= n; i++) 
			scanf("%d%d", &p[i].first, &p[i].second);
		ac.init();

		int k;
		while (m--) {
			scanf("%d", &k);
			for (int i = 0; i < k; i++)
				scanf("%d", &a[i]);
			ac.insert(a, k);
		}

		ac.build();
		ac.solve();
	}
	return 0;
}

HDU - 4511 小明系列故事――女友的考验(AC自动机+DP)

原文：http://blog.csdn.net/u011345136/article/details/40052181