HDU 2457 DNA repair

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 const int INF = 0x3f3f3f3f;
 4 const int maxn = 1010;
 5 char str[maxn];
 6 int dp[maxn][maxn],id[130],n,cs = 1;
 7 
 8 struct Trie {
 9     int ch[maxn][4],fail[maxn],tot;
10     bool flag[maxn];
11     int newnode() {
12         memset(ch[tot],0,sizeof ch[tot]);
13         fail[tot] = flag[tot] = 0;
14         return tot++;
15     }
16     void init() {
17         tot = 0;
18         newnode();
19     }
20     void insert(char *str,int root = 0){
21         for(int i = 0; str[i]; ++i){
22             if(!ch[root][id[str[i]]]) ch[root][id[str[i]]] = newnode();
23             root = ch[root][id[str[i]]];
24         }
25         flag[root] = true;
26     }
27     void build(int root = 0) {
28         queue<int>q;
29         for(int i = 0; i < 4; ++i) {
30             if(ch[root][i]) {
31                 fail[ch[root][i]] = root;
32                 q.push(ch[root][i]);
33             }
34         }
35         while(!q.empty()) {
36             root = q.front();
37             q.pop();
38             for(int i = 0; i < 4; ++i) {
39                 int &nx = ch[root][i];
40                 if(nx) {
41                     fail[nx] = ch[fail[root]][i];
42                     flag[nx] = flag[nx]||flag[fail[nx]];
43                     q.push(nx);
44                 } else nx = ch[fail[root]][i];
45             }
46         }
47     }
48     void solve(char *str) {
49         memset(dp,0x3f,sizeof dp);
50         int len = strlen(str);
51         dp[0][0] = 0;
52         for(int i = 0; i < len; ++i)
53             for(int j = 0; j < tot; ++j) {
54                 if(dp[i][j] >= INF) continue;
55                 for(int k = 0; k < 4; ++k) {
56                     int nx = ch[j][k];
57                     if(flag[nx]) continue;
58                     dp[i+1][nx] = min(dp[i+1][nx],dp[i][j] + (id[str[i]] != k));
59                 }
60             }
61         int ret = INF;
62         for(int i = 0; i < tot; ++i)
63             ret = min(ret,dp[len][i]);
64         printf("Case %d: %d\n",cs++,ret == INF?-1:ret);
65     }
66 } ac;
67 int main() {
68     for(int i = 0; i < 4; ++i) id["ATCG"[i]] = i;
69     while(scanf("%d",&n),n) {
70         ac.init();
71         for(int i = 0; i < n; ++i) {
72             scanf("%s",str);
73             ac.insert(str);
74         }
75         ac.build();
76         scanf("%s",str);
77         ac.solve(str);
78     }
79     return 0;
80 }