HDU 2296 Ring

 1 #include <bits/stdc++.h>
 2 using namespace std;
 3 using PII = pair<int,int>;
 4 const int maxn = 510;
 5 
 6 struct Trie{
 7     int ch[maxn][26],fail[maxn],cnt[maxn],tot;
 8     int dp[maxn][maxn];
 9     PII path[maxn][maxn];
10     int newnode(){
11         memset(ch[tot],0,sizeof ch[tot]);
12         fail[tot] = cnt[tot] = 0;
13         return tot++;
14     }
15     void init(){
16         tot = 0;
17         newnode();
18     }
19     void insert(char *str,int val,int rt = 0){
20         for(int i = 0; str[i]; ++i){
21             int &x = ch[rt][str[i]-‘a‘];
22             if(!x) x = newnode();
23             rt = x;
24         }
25         cnt[rt] += val;
26     }
27     void build(int rt = 0){
28         queue<int>q;
29         for(int i = 0; i < 26; ++i)
30             if(ch[rt][i]) q.push(ch[rt][i]);
31         while(!q.empty()){
32             rt = q.front();
33             q.pop();
34             cnt[rt] += cnt[fail[rt]];
35             for(int i = 0; i < 26; ++i){
36                 int &x = ch[rt][i],y = ch[fail[rt]][i];
37                 if(x){
38                     fail[x] = y;
39                     q.push(x);
40                 }else x = y;
41             }
42         }
43     }
44     void solve(int n){
45         memset(dp,0,sizeof dp);
46         for(int i = n; i; --i){
47             for(int j = 0; j < tot; ++j){
48                 for(int k = 0; k < 26; ++k){
49                     int x = ch[j][k],tmp = dp[i+1][x] + cnt[x];
50                     if(tmp > dp[i][j]){
51                         dp[i][j] = tmp;
52                         path[i][j] = PII(x,k);
53                     }
54                 }
55             }
56         }
57         int pos = n + 1,ans = 0,st = 0;
58         for(int i = n + 1; i; --i)
59             if(dp[i][0] > ans) ans = dp[pos = i][0];
60         for(int i = pos; i <= n; ++i){
61             printf("%c",path[i][st].second + ‘a‘);
62             st = path[i][st].first;
63         }
64         putchar(‘\n‘);
65     }
66 }ac;
67 char str[maxn][maxn];
68 int main(){
69     int kase,n,m,val;
70     scanf("%d",&kase);
71     while(kase--){
72         scanf("%d%d",&n,&m);
73         for(int i = 0; i < m; ++i)
74             scanf("%s",str[i]);
75         ac.init();
76         for(int i = 0; i < m; ++i){
77             scanf("%d",&val);
78             ac.insert(str[i],val);
79         }
80         ac.build();
81         ac.solve(n);
82     }
83     return 0;
84 }