POJ 1625 Censored!

AC自动机 + DP + 大数。网上说矩阵过不去，写了一发样例都没调出来直接放弃了。由于习惯性的把数组开大了，爆了两次，然后直接A了。注意大数为0的输出

#include<cstdio>
#include<string>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<iostream>
using namespace std;
#define N 2005
#define INF 1000000009
typedef long long LL;
int n;
int letter[300];
struct Trie {
    Trie *fail;
    Trie *son[300];
    int kind,isword;
}s[N];
Trie *que[N];
int ptr;
int id(unsigned char x){
    return letter[x];
}
Trie *NewNode(){
    Trie *p = &s[ptr];
    for(int i = 0; i < n; i++)p->son[i] = NULL;
    p->fail = NULL;
    p->isword = 0;
    p->kind = ptr++;
    return p;
}
void Insert(unsigned char *c,Trie *root){
    Trie *tmp = root;
    for(int i = 0; c[i]; i++){
        if(tmp->son[id(c[i])] == NULL) tmp->son[id(c[i])] = NewNode();
        tmp = tmp->son[id(c[i])];
    }
    tmp->isword = 1;
}
void Build_fail(Trie *root){
    Trie *tmp;
    int head = 0,tail = 0;
    que[tail++] = root;
    root->fail = NULL;
    while(head < tail){
        tmp = que[head++];
        for(int i = 0; i < n; i++){
            if(tmp->son[i]){
                if(tmp == root)tmp->son[i]->fail = root;
                else {
                    Trie *p = tmp->fail;
                    while(p){
                        if(p->son[i]){
                            tmp->son[i]->fail = p->son[i];
                            break;
                        }
                        p = p->fail;
                    }
                    if(p == NULL)tmp->son[i]->fail = root;
                }
                if(tmp->son[i]->fail->isword)tmp->son[i]->isword = 1;
                que[tail++] = tmp->son[i];
            }
            else if(tmp == root)tmp->son[i] = root;
            else tmp->son[i] = tmp->fail->son[i];
        }
    }
}
#define length 100
class Bignum{
    char s[length * 2];
public :
    Bignum(int x = 0){
        memset(s,sizeof(s));
        s[0] = x;
    }
    void setnum(int x){
        for(int i = 0; x; i++){
            s[i] = x % 10;
            x /= 10;
        }
    }
    Bignum operator+(Bignum x){
        Bignum ans;
        for(int i = 0; i < length; i++){
            ans.s[i] += s[i] + x.s[i];
            ans.s[i + 1] += ans.s[i] / 10;
            ans.s[i] %= 10;
        }
        return ans;
    }
    void print(){
        int i = length;
        while(s[i] == 0 && i >= 0)i--;
        if(i == -1)printf("0");
        while(i >= 0)printf("%d",s[i--]);
        printf("n");
    }
}dp[55][105];
void solve(int tot){
    dp[0][0].setnum(1);
    Bignum zero;
    for(int i = 1; i <= tot; i++){
        for(int j = 0; j < ptr; j++){
            Trie *tmp = &s[j];
            if(tmp->isword)continue;
            for(int k = 0; k < n; k++){
                if(tmp->son[k]->isword)continue;
                dp[i][tmp->son[k]->kind] = dp[i][tmp->son[k]->kind] + dp[i - 1][j];
            }
        }
    }
    Bignum ans;
    for(int i = 0; i < ptr; i++){
        ans = ans + dp[tot][i];
    }
    ans.print();
}
int main(){
    int m,p;
    while(scanf("%d%d%d",&n,&m,&p) != EOF){
        ptr = 0;
        Trie *root = NewNode();
        unsigned char str[20];
        unsigned char ms[55];
        scanf("%s",ms);
        memset(letter,sizeof(letter));
        for(int i = 0; ms[i]; i++)
            letter[ms[i]] = i;
        for(int i = 0; i < p; i++){
            scanf("%s",str);
            Insert(str,root);
        }
        Build_fail(root);
        solve(m);
    }
    return 0;
}