UVA 11468 Substring (记忆化搜索 + AC自动鸡)

#include <bits/stdc++.h>
#define LL long long
#define rep(i, j, k) for(int i = j; i <= k; i++)
#define dep(i, j, k) for(int i = k; i >= j; i--)
#define INF 0x3f3f3f3f
#define inf 0x3f3f3f3f3f3f3f3f
#define mem(i, j) memset(i, j, sizeof(i))
#define pb push_back
using namespace std;

const int N = 20 * 20 + 5, M = 105;
char op[2];
double tmp;
struct Trie {
    int a[N][M], tot, metch[N], Fail[N], vis[N][M], n;
    double p[N], dp[N][M];
    char ch[M];
    void init() {
        mem(a[0], 0); tot = 1; metch[0] = 0; mem(dp, 0); mem(p, 0); mem(vis, 0);
    }
    int get(char Q) {
        if(Q >= ‘0‘ && Q <= ‘9‘) return Q - ‘0‘ + 1;
        if(Q >= ‘A‘ && Q <= ‘Z‘) return Q - ‘A‘ + 11;
        return Q - ‘a‘ + 37;
    }
    void join(char s[]) {
        int now = 0; int len = strlen(s);
        rep(i, 0, len - 1) {
            int id = get(s[i]);
            if(!a[now][id]) {
                mem(a[tot], 0); metch[tot] = 0;
                a[now][id] = tot++;
            }
            now = a[now][id];
        }
        metch[now] = 1;
    }
    void getFail() {
        queue<int> Q; while(!Q.empty()) Q.pop();
        rep(i, 1, M - 1) {
            if(a[0][i]) {
                Q.push(a[0][i]); Fail[a[0][i]] = 0;
            }
        }
        while(!Q.empty()) {
            int now = Q.front(); Q.pop();
            rep(i, 1, M - 1) {
                int u = a[now][i];
                if(u == 0) a[now][i] = a[Fail[now]][i];
                else {
                    Q.push(u);
                    Fail[u] = a[Fail[now]][i];
                    metch[u] |= metch[Fail[u]];
                }
            }
        }
    }
    double dfs(int now, int L) {
        if(!L) return 1.0;
        if(vis[now][L]) return dp[now][L];
        vis[now][L] = 1;
        double &ans = dp[now][L];
        ans = 0.0;
        rep(i, 1, M - 1) { /// 枚举所有可能字符
            if(!metch[a[now][i]]) { /// 这个节点可以走
                ans += p[i] * dfs(a[now][i], L - 1);
            }
        }
        return ans;
    }
    void scan() {
        scanf("%d", &n);
        rep(i, 1, n) {
            scanf("%s %lf", op, &tmp);
            int id = get(op[0]);
            p[id] = tmp;
        }
    }
    void print(int cas) {
        int L; scanf("%d", &L);
        printf("Case #%d: ", cas);
        printf("%.6f\n", dfs(0, L));
    }
};
Trie AC;
char b[25];
int main() {
    int _; scanf("%d", &_); int cas = 0;
    while(_--) {
        AC.init();
        int k; scanf("%d", &k);
        rep(i, 1, k) {
            scanf("%s", b); AC.join(b);
        }
        AC.getFail();
        AC.scan();
        AC.print(++cas);
    }
    return 0;
}