UVa 11468 (AC自动机 概率DP) Substring

#include <cstdio>
#include <cstring>
#include <queue>
using namespace std;

const int maxnode = 500;
const int sigma_size = 64;
int idx[256];

struct AhoCorasickAutomata
{
int ch[maxnode][sigma_size];
int match[maxnode];
int f[maxnode];
int sz;

void init() { sz = 1; memset(ch[0], 0, sizeof(ch[0])); }

void insert(char* s)
{
int u = 0, n = strlen(s);
for(int i = 0; i < n; i++)
{
int c = idx[s[i]];
if(!ch[u][c])
{
memset(ch[sz], 0, sizeof(ch[sz]));
match[sz] = 0;
ch[u][c] = sz++;
}
u = ch[u][c];
}
match[u] = 1;
}

void getFail()
{
queue<int> q;
f[0] = 0;
for(int c = 0; c < sigma_size; c++)
{
int u = ch[0][c];
if(u) { f[u] = 0; q.push(u); }
}
while(!q.empty())
{
int r = q.front(); q.pop();
for(int c = 0; c < sigma_size; c++)
{
int u = ch[r][c];
if(!u) { ch[r][c] = ch[f[r]][c]; continue; }
q.push(u);
int v = f[r];
while(v && !ch[v][c]) v = f[v];
f[u] = ch[v][c];
match[u] |= match[f[u]];
}
}
}
}ac;

int n;
const int maxl = 100 + 10;
char s[30][30];
double prob[sigma_size];

int vis[maxnode][maxl];
double d[maxnode][maxl];

double getProb(int u, int L)
{
if(L == 0) return 1.0;
if(vis[u][L]) return d[u][L];
vis[u][L] = 1;
double& ans = d[u][L];
ans = 0;
for(int c = 0; c < n; c++)
if(!ac.match[ac.ch[u][c]])
ans += prob[c] * getProb(ac.ch[u][c], L-1);
return ans;
}

int main()
{
//freopen("in.txt", "r", stdin);

int T;
scanf("%d", &T);
for(int kase = 1; kase <= T; kase++)
{
int k, L;
scanf("%d", &k);
for(int i = 0; i < k; i++) scanf("%s", s[i]);

scanf("%d", &n);
for(int i = 0; i < n; i++)
{
char s1[9];
scanf("%s%lf", s1, &prob[i]);
idx[s1[0]] = i;
}

ac.init();
for(int i = 0; i < k; i++) ac.insert(s[i]);
ac.getFail();
scanf("%d", &L);
memset(vis, 0, sizeof(vis));
printf("Case #%d: %.6f\n", kase, getProb(0, L));
}

return 0;
}