• AC自动机


    hdu 4758

    题意:求长度为n+m,有n个0,且必须包含串s1和s2的串的个数,s1和s2可以重叠;

    太久没写AC了,导致比赛的时候很裸的AC自动机的题目都没有往那边想,唉~

    比赛的时候就想到状态dp[i][4],但是发现在某一时候在末尾加入s1后会把s2也引入,就是状态转移想不清楚;然后就没有然后了;

    AC自动机,通过建AC自动机,得出在任何一个状态下s1,s2出现的情况记录在val[]里,这样用dp[len][i][n][state]状态(表示长度为len的串,最后一个字符在AC自动机里的结点I位,0的个数为n,s1,s2的出现情况的个数)就可以DP了;

      1 #include<cstdio>
      2 #include<cstring>
      3 #include<cstdlib>
      4 #include<vector>
      5 #include<cmath>
      6 #include<algorithm>
      7 #include<iostream>
      8 #include<queue>
      9 using namespace std;
     10 typedef long long LL;
     11 const int maxnode = 200+10;
     12 const int sigma_sz = 2;
     13 const int N = 210;
     14 const int Mod = 1000000007;
     15 int dp[2][maxnode][110][4];
     16 int n,m;
     17 struct AC{
     18     int ch[maxnode][sigma_sz];
     19     int f[maxnode],val[maxnode];
     20     int sz;
     21     queue<int> q;
     22     void init(){
     23         sz = 1;
     24         memset(ch[0],0,sizeof(ch[0]));
     25         memset(val,0,sizeof(val));
     26     }
     27     int idx(char c) {
     28         if (c == 'R') return 0;
     29         return 1;
     30     }
     31     void insert(char *s,int id) {
     32         int len = strlen(s), u = 0;
     33         for (int i = 0; i < len; i++) {
     34             int c = idx(s[i]);
     35             if (ch[u][c] == 0) {
     36                 memset(ch[sz],0,sizeof(ch[sz]));
     37                 ch[u][c] = sz++;
     38             }
     39             u = ch[u][c];
     40         }
     41         val[u] = id;
     42     }
     43     void getFail(){
     44         while (!q.empty()) q.pop();
     45         for (int i = 0; i < sigma_sz; i++) {
     46             int c = ch[0][i];
     47             if (c)  {
     48                 f[c] = 0; q.push(c);
     49             }
     50         }
     51         while (!q.empty()) {
     52             int u = q.front(); q.pop();
     53             for (int i = 0; i < sigma_sz; i++) {
     54                 int v = ch[u][i];
     55                 if (v) {
     56                     q.push(v);
     57                     int r = f[u];
     58                     while (r && ch[r][i] == 0) r = f[r];
     59                     f[v] = ch[r][i];
     60                     val[v] |= val[f[v]];
     61                 }else {
     62                     ch[u][i] = ch[f[u]][i];
     63                 }
     64             }
     65         }
     66     }
     67     void solve(){
     68         getFail();
     69         int pos = 0;
     70         dp[pos][0][0][0] = 1;
     71         for (int i = 0 ; i < n+m; i++) {
     72             for (int j = 0; j < sz; j++){
     73                 for (int x = 0; x <= i; x++) {
     74                     for (int y = 0; y <= 3; y++) {
     75                         for (int k = 0; k < sigma_sz; k++) {
     76                             int c = ch[j][k];
     77                             int f = (k == 0 ? 1 : 0);
     78                             dp[pos^1][c][x+f][y|val[c]] += dp[pos][j][x][y];
     79                             dp[pos^1][c][x+f][y|val[c]] %= Mod;
     80                         }
     81                     }
     82                 }
     83             }
     84             memset(dp[pos],0,sizeof(dp[pos]));
     85             pos ^= 1;
     86         }
     87         LL ret = 0;
     88         for (int i = 0; i < sz; i++) {
     89             ret = (ret + dp[pos][i][n][3]) % Mod;
     90         }
     91         printf("%lld
    ",ret);
     92     }
     93 
     94 }H;
     95 char s[110];
     96 void solve(){
     97     memset(dp,0,sizeof(dp));
     98     H.solve();
     99 }
    100 int main(){
    101     int T; scanf("%d",&T);
    102     while (T--) {
    103         scanf("%d%d",&n,&m);
    104         H.init();
    105         for (int i = 0; i < 2; i++) {
    106             scanf("%s",s);
    107             H.insert(s,1<<i);
    108         }
    109         solve();
    110     }
    111     return 0;
    112 }
    View Code

     UVALive 3942

      1 #include<cstdio>
      2 #include<cstring>
      3 #include<cstdlib>
      4 #include<vector>
      5 #include<algorithm>
      6 #include<cmath>
      7 #include<queue>
      8 using namespace std;
      9 const int N = 300000+10;
     10 const int maxnode = 400000+10;
     11 const int sigma_sz = 26;
     12 const int Mod = 20071027;
     13 int dp[N];
     14 struct AC{
     15     int ch[maxnode][sigma_sz];
     16     int sz;
     17     queue<int> q;
     18     int val[maxnode], le[maxnode], last[maxnode], f[maxnode];//le[] > 0 is ends
     19     void init(){
     20         sz = 1;
     21         memset(val,0,sizeof(val));
     22         memset(le,0,sizeof(le));
     23         memset(ch[0],0,sizeof(ch[0]));
     24     }
     25     int idx(char c) {
     26         return c - 'a';
     27     }
     28     void insert(char *s) {
     29         int len = strlen(s), u = 0;
     30         for (int i = 0; i < len; i++) {
     31             int v = idx(s[i]);
     32             if (ch[u][v] == 0) {
     33                 memset(ch[sz],0,sizeof(ch[sz]));
     34                 ch[u][v] = sz++;
     35             }
     36             u = ch[u][v];
     37         }
     38         val[u] = 1;
     39         le[u] = len;
     40     }
     41     void getFail() {
     42         while (!q.empty()) q.pop();
     43         for (int i = 0; i < sigma_sz; i++) {
     44             int v = ch[0][i];
     45             if (v) {
     46                 q.push(v); f[v] = 0; last[v] = 0;
     47             }
     48         }
     49         while (!q.empty()) {
     50             int u = q.front(); q.pop();
     51             for (int i = 0; i < sigma_sz; i++) {
     52                 int v = ch[u][i];
     53                 if (v) {
     54                     q.push(v);
     55                     int r = f[u];
     56                     while (r && ch[r][i] == 0) r = f[r];
     57                     f[v] = ch[r][i];
     58                     val[v] |= val[f[v]];
     59                     last[v] = le[f[v]] ? f[v] : last[f[v]];
     60                 }else {
     61                     ch[u][i] = ch[f[u]][i];
     62                 }
     63             }
     64         }
     65     }
     66     void solve(char *T){
     67         int len = strlen(T);
     68         int u = 0;
     69         for (int i = 1; i < len; i++) {
     70             int c = idx(T[i]);
     71             int r = ch[u][c];
     72             if (val[r]) {
     73                 int j = r;
     74                 while (j) {
     75                     if (le[j]) dp[i] = (dp[i] + dp[i - le[j]] ) % Mod;
     76                     j = last[j];
     77                 }
     78 
     79             }
     80             u = ch[u][c];
     81         }
     82     }
     83 }H;
     84 int n;
     85 char text[N],p[N];
     86 void solve(){
     87     memset(dp,0,sizeof(dp));
     88     dp[0] = 1;
     89     H.solve(text);
     90     printf("%d
    ",dp[strlen(text)-1]);
     91 }
     92 int main(){
     93     int cas = 0;
     94     text[0] = '#';
     95     while (~scanf("%s",text+1)) {
     96         scanf("%d",&n);
     97         H.init();
     98         for (int i = 0; i < n; i++) {
     99             scanf("%s",p);
    100             H.insert(p);
    101         }
    102         H.getFail();
    103         printf("Case %d: ",++cas);
    104         solve();
    105     }
    106     return 0;
    107 }
    108 /*
    109 abcd
    110 4
    111 a
    112 b
    113 cd
    114 ab
    115 heshehishers
    116 7
    117 s
    118 h
    119 e
    120 he
    121 she
    122 his
    123 hers
    124 
    125 */
    View Code

    UALive 4670

      1 #include<cstdio>
      2 #include<cstring>
      3 #include<cstdlib>
      4 #include<vector>
      5 #include<algorithm>
      6 #include<iostream>
      7 #include<queue>
      8 using namespace std;
      9 const int maxnode = 15000+10;
     10 const int sigma_sz = 26;
     11 const int N = 1000000+10;
     12 int cnt[N];
     13 struct AC{
     14     int ch[maxnode][sigma_sz];
     15     int f[maxnode],val[maxnode],isend[maxnode],last[maxnode];
     16     int sz;
     17     queue<int> q;
     18     void init(){
     19         sz = 1;
     20         memset(val,0,sizeof(val));
     21         memset(isend,0,sizeof(isend));
     22         memset(ch[0],0,sizeof(ch[0]));
     23     }
     24     int idx(char c) {
     25         return c - 'a';
     26     }
     27     void insert(char *s,int id){
     28         int len = strlen(s), u = 0;
     29         for (int i = 0; i < len; i++) {
     30             int c = idx(s[i]);
     31             if (ch[u][c] == 0) {
     32                 memset(ch[sz],0,sizeof(ch[sz]));
     33                 ch[u][c] = sz++;
     34             }
     35             u = ch[u][c];
     36         }
     37         val[u] = 1; isend[u] = id;
     38     }
     39     void getFail(){
     40         while (!q.empty()) q.pop();
     41         for (int i = 0; i < sigma_sz; i++) {
     42             int c = ch[0][i];
     43             if (c) {
     44                 f[c] = 0; last[c] = 0; q.push(c);
     45             }
     46         }
     47         while (!q.empty()) {
     48             int u = q.front(); q.pop();
     49             for (int i = 0; i < sigma_sz; i++) {
     50                 int v = ch[u][i];
     51                 if (v) {
     52                     q.push(v);
     53                     int r = f[u];
     54                     while (r && ch[r][i] == 0) r = f[r];
     55                     f[v] = ch[r][i];
     56                     val[v] |= val[f[v]];
     57                     last[v] = isend[f[v]] ? f[v] : last[f[v]];
     58                 }else {
     59                     ch[u][i] = ch[f[u]][i];
     60                 }
     61             }
     62         }
     63     }
     64     void solve(char *T){
     65         getFail();
     66         int len = strlen(T), u = 0;
     67         for (int i = 0; i < len; i++) {
     68             int c = idx(T[i]);
     69             u = ch[u][c];
     70             int j = u;
     71             if (val[j]) {
     72                 while (j) {
     73                     if (isend[j]) cnt[isend[j]]++;
     74                     j = last[j];
     75                 }
     76             }
     77         }
     78     }
     79 }H;
     80 int n;
     81 char text[N],p[200][80];
     82 void solve(){
     83     H.solve(text);
     84 
     85     int mx = 0;
     86     for (int i = 1; i <= n; i++) {
     87         if (cnt[i] > mx) mx = cnt[i];
     88     }
     89     printf("%d
    ",mx);
     90     for (int i = 1 ; i <= n; i++) {
     91         if (cnt[i] == mx) printf("%s
    ",p[i]);
     92     }
     93 
     94 }
     95 int main(){
     96     while (~scanf("%d",&n),n) {
     97         memset(cnt,0,sizeof(cnt));
     98         H.init();
     99         for (int i = 1 ; i <= n; i++) {
    100             scanf("%s",p[i]);
    101            // cout<<p[i]<<endl;
    102             H.insert(p[i],i);
    103         }
    104         scanf("%s",text);
    105         solve();
    106     }
    107     return 0;
    108 }
    View Code
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  • 原文地址:https://www.cnblogs.com/Rlemon/p/3332439.html
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