HDU 2457 DNA repair AC自动机 + dp

#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <assert.h>
#define IOS ios::sync_with_stdio(false)
using namespace std;
#define inf (0x3f3f3f3f)
typedef long long int LL;


#include <iostream>
#include <sstream>
#include <vector>
#include <set>
#include <map>
#include <queue>
#include <string>
#include <bitset>
int n;
const int maxn = 50 + 20;
const int N = 4;
struct node {
    int flag;
    struct node *Fail;    //失败指针，匹配失败，跳去最大前后缀
    struct node *pNext[N];
    int id;
} tree[maxn * 20];
int t;    //字典树的节点
struct node *create() {
    //其实也只是清空数据而已
    struct node *p = &tree[t++];
    p->flag = 0;
    p->Fail = NULL;
    p->id = t - 1;
    for (int i = 0; i < N; i++) {
        p->pNext[i] = NULL;
    }
    return p;
}
int getid(char ch) {
    if (ch == ‘A‘) return 0;
    else if (ch == ‘G‘) return 1;
    else if (ch == ‘C‘) return 2;
    else return 3;
}
void toinsert(struct node **T, char str[]) {
    struct node *p = *T;
    if (p == NULL) {
        p = *T = create();
    }
    for (int i = 1; str[i]; i++) {
        int id = getid(str[i]);
        if (p->pNext[id] == NULL) {
            p->pNext[id] = create();
        }
        p = p->pNext[id];
    }
    p->flag++;    //相同的单词算两次
    return ;
}
void BuiltFail(struct node **T) {
    //根节点没有失败指针,所以都是需要特判的
    //思路就是去到爸爸的失败指针那里，找东西匹配，这样是最优的
    struct node *p = *T; //用个p去代替修改
    struct node *root = *T;
    if (p == NULL) return ;
    //树上bfs,要更改的是p->pNext[i]->Fail
    struct node *que[t + 20]; //这里的t是节点总数，字典树那里统计的
    int head = 0, tail = 0;
    que[tail++] = root;
    while (head < tail) {
        p = que[head]; //p取出第一个元素 ★
        for (int i = 0; i < N; i++) { //看看存不存在这个节点
            if (p->pNext[i] != NULL) { //存在的才需要管
                if (p == root) { //如果爸爸是根节点的话
                    p->pNext[i]->Fail = root; //指向根节点
                } else {
                    struct node *FailNode = p->Fail; //首先找到爸爸的失败指针
                    while (FailNode != NULL) {
                        if (FailNode->pNext[i] != NULL) { //存在
                            p->pNext[i]->Fail = FailNode->pNext[i];
                            break;
                        }
                        FailNode = FailNode->Fail; //回溯
                    }
                    if (FailNode == NULL) { //如果还是空，那么就指向根算了
                        p->pNext[i]->Fail = root;
                    }
                }
                if (p->pNext[i]->Fail->flag) {
                    p->pNext[i]->flag = 1; //它是病毒，我也是病毒。
                }
                que[tail++] = p->pNext[i]; 
            } else if (p == root) {  //变化问题
                p->pNext[i] = root;
            } else {
                p->pNext[i] = p->Fail->pNext[i];
            }
        }
        head++;
    }
    return ;
}
char str[1111];
int lenstr, dp[1111][1111];
void work() {
    t = 0;
    struct node *T = NULL;
    for (int i = 1; i <= n; ++i) {
        scanf("%s", str + 1);
        toinsert(&T, str);
    }
    scanf("%s", str + 1);
    lenstr = strlen(str + 1);
    for (int i = 1; i <= lenstr; ++i) str[i] = getid(str[i]);
    BuiltFail(&T);
    --t;
    for (int i = 0; i <= lenstr; ++i) {
        for (int j = 0; j <= t; ++j) {
            dp[i][j] = inf;
        }
    }
    dp[0][0] = 0;
    for (int i = 1; i <= lenstr; ++i) {
        for (int j = 0; j <= t; ++j) {
            if (dp[i - 1][j] == inf) continue;
            for (int k = 0; k < 4; ++k) {
                if (tree[j].pNext[k]->flag) continue; //bad串
                int s = tree[j].pNext[k]->id;
                dp[i][s] = min(dp[i][s], dp[i - 1][j] + (str[i] != k));
            }
        }
    }
    int ans = inf;
    for (int i = 0; i <= t; ++i) {
        ans = min(ans, dp[lenstr][i]);
    }
    if (ans == inf) ans = -1;
    static int gg = 0;
    printf("Case %d: %d\n", ++gg, ans);

}

int main() {
#ifdef local
    freopen("data.txt", "r", stdin);
//    freopen("data.txt", "w", stdout);
#endif
    while (scanf("%d", &n) != EOF && n) work();
    return 0;
}