zju3545
AC自动机+状态压缩DP
注意：相同的串可能出现多次，如果匹配成功则将各次权值加和。
#include <cstdio> #include <queue> #include <cstring> using namespace std; #define D(x) const int MAX_N = 15; const int MAX_LEN = 105; const int MAX_CHILD_NUM = 4; const int MAX_NODE_NUM = MAX_LEN * MAX_N; //1.init() 2.insert() 3.build() 4.query() struct Trie { int next[MAX_NODE_NUM][MAX_CHILD_NUM]; int fail[MAX_NODE_NUM]; int count[MAX_NODE_NUM]; int node_cnt; bool vis[MAX_NODE_NUM]; //set it to false int root; void init() { node_cnt = 0; root = newnode(); memset(vis, 0, sizeof(vis)); } int newnode() { for (int i = 0; i < MAX_CHILD_NUM; i++) next[node_cnt][i] = -1; count[node_cnt++] = 0; return node_cnt - 1; } int get_id(char a) { if (a == 'A') return 0; if (a == 'T') return 1; if (a == 'C') return 2; return 3; } void insert(char buf[], int id) { int now = root; for (int i = 0; buf[i]; i++) { int id = get_id(buf[i]); if (next[now][id] == -1) next[now][id] = newnode(); now = next[now][id]; } count[now] |= (1 << id); } void build() { queue<int>Q; fail[root] = root; for (int i = 0; i < MAX_CHILD_NUM; i++) if (next[root][i] == -1) next[root][i] = root; else { fail[next[root][i]] = root; Q.push(next[root][i]); } while (!Q.empty()) { int now = Q.front(); Q.pop(); for (int i = 0; i < MAX_CHILD_NUM; i++) if (next[now][i] == -1) next[now][i] = next[fail[now]][i]; else { fail[next[now][i]]=next[fail[now]][i]; count[next[now][i]] |= count[fail[next[now][i]]]; Q.push(next[now][i]); } } } int query(char buf[]) { int now = root; int res = 0; memset(vis, 0, sizeof(vis)); for (int i = 0; buf[i]; i++) { now = next[now][get_id(buf[i])]; int temp = now; while (temp != root && !vis[temp]) { res += count[temp]; // optimization: prevent from searching this fail chain again. //also prevent matching again. vis[temp] = true; temp = fail[temp]; } } return res; } void debug() { for(int i = 0;i < node_cnt;i++) { printf("id = %3d,fail = %3d,end = %3d,chi = [",i,fail[i],count[i]); for(int j = 0;j < MAX_CHILD_NUM;j++) printf("%2d",next[i][j]); printf("]\n"); } } }ac; const int MAX_STATUS = (1 << 10) + 20; int n, len; char st[MAX_LEN]; int w[MAX_N]; bool dp[2][MAX_NODE_NUM][MAX_STATUS]; int cal(int status) { int ret = 0; for (int i = 0; i < n; i++) { if (status & (1 << i)) ret += w[i]; } return ret; } int work() { int ret = -1; memset(dp, 0, sizeof(dp)); dp[0][ac.root][0] = true; for (int i = 0; i < len; i++) { for (int j = 0; j < ac.node_cnt; j++) for (int status = 0; status < (1 << n); status++) dp[(i + 1) & 1][j][status] = false; D(printf("%d\n", dp[(i + 1) & 1][2][0])); for (int j = 0; j < ac.node_cnt; j++) { for (int status = 0; status < (1 << n); status++) { if (!dp[i & 1][j][status]) continue; for (int k = 0; k < 4; k++) { int v = ac.next[j][k]; dp[(i + 1) & 1][v][status | ac.count[v]] = true; D(printf("%d %d\n", j, status)); D(printf("%d %d %d %d\n", (i + 1) & 1, v, status | ac.count[v], dp[(i + 1) & 1][0][1044])); } } } } for (int i = 0; i < ac.node_cnt; i++) for (int status = 0; status < (1 << n); status++) { if (dp[len & 1][i][status]) { if (dp[len & 1][i][0] && status == 0) { D(printf("*%d %d\n", i, ac.count[i])); } ret = max(ret, cal(status)); } } return ret; } int main() { while (scanf("%d%d", &n, &len) != EOF) { ac.init(); for (int i = 0; i < n; i++) { scanf("%s%d", st, &w[i]); ac.insert(st, i); } ac.build(); int ans = work(); if (ans < 0) puts("No Rabbit after 2012!"); else printf("%d\n", ans); } return 0; }