hdu 6208 The Dominator of Strings【AC自动机】
hdu 6208 The Dominator of Strings【AC自动机】
求一个串包含其他所有串，找出最长串去匹配即可，但是匹配时要对走过的结点标记，不然T死QAQ，，扎心了。。
1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 #include<queue> 6 using namespace std; 7 inline void read(int&a){char c;while(!(((c=getchar())>='0')&&(c<='9')));a=c-'0';while(((c=getchar())>='0')&&(c<='9'))(a*=10)+=c-'0';} 8 const int N = 100005; 9 const int M = 26; 10 struct Trie { 11 int next[N][M], fail[N], tag[N]; 12 int root; 13 int vis[N]; 14 int L; 15 int newnode() { 16 for(int i = 0;i < M;i++) 17 next[L][i] = -1; 18 vis[L] = 0; 19 tag[L++] = 0; 20 21 return L-1; 22 } 23 void init() { 24 L = 0; 25 root = newnode(); 26 } 27 void Insert(char buf[]) { 28 int len = strlen(buf); 29 int u = root; 30 for(int i = 0; i < len; i++) { 31 if(next[u][buf[i]-'a'] == -1) 32 next[u][buf[i]-'a'] = newnode(); 33 u = next[u][buf[i]-'a']; 34 } 35 tag[u]++; 36 } 37 void build() { 38 queue<int> Q; 39 fail[root] = root; 40 for(int i = 0; i < M; i++) { 41 if(next[root][i] == -1) 42 next[root][i] = root; 43 else { 44 fail[next[root][i]] = root; 45 Q.push(next[root][i]); 46 } 47 } 48 while( !Q.empty() ) { 49 int u = Q.front(); 50 Q.pop(); 51 for(int i = 0; i < M; i++) { 52 int &v = next[u][i]; 53 if(v == -1) 54 v = next[fail[u]][i]; 55 else { 56 Q.push(v); 57 fail[v] = next[fail[u]][i]; 58 } 59 } 60 } 61 } 62 int query(char buf[]) { 63 int len = strlen(buf); 64 int u = root; 65 int res = 0; 66 for(int i = 0; i < len; i++) { 67 u = next[u][buf[i]-'a']; 68 int t = u; 69 while( t != root && !vis[t] ) { 70 res += tag[t]; 71 72 vis[t] = 1;//要不然会t啊 73 74 tag[t] = 0; 75 t = fail[t]; 76 77 } 78 } 79 return res; 80 } 81 }; 82 char s[N]; 83 char ss[N]; 84 Trie ac; 85 int main() { 86 int t, n; 87 read(t); 88 while(t--){ 89 int ma = 0; 90 ac.init(); 91 read(n); 92 93 for(int i=0; i<n; i++){ 94 scanf("%s",s); 95 int len = strlen(s); 96 ac.Insert(s); 97 if(ma <= len){ 98 ma = len; strcpy(ss, s); 99 } 100 } 101 ac.build(); 102 int ans = ac.query(ss); 103 if(ans == n){ 104 printf("%s\n",ss); 105 } 106 else printf("No\n"); 107 } 108 return 0; 109 }
