poj 3691 DNA repair

http://poj.org/problem?id=3691

AC自动机+DP

代码：

#include<iostream>
#include<cmath>
#include<cstdio>
#include<string>
#include<cstring>
#include<vector>
#include<stack>
#include<queue>
#include<set>
#include<map>
#include<algorithm>

#define LL long long

using namespace std;

const int INF=0x3f3f3f3f;
const int MOD=20090717;
const LL LMOD=100000;
const int N=1010;
const int M=1010;
const int K=4;
struct nodeTrie
{
    int v;
    int fail;
    int next[K];
    void initialize()
    {
        v=0;
        fail=-1;
        memset(next,-1,sizeof(next));
    }
}trie[M];
int cnt,root;
char s[N];
int to[M][K];
int dp[N][M];
map<char,int>mt;
int getNewNode()
{
    ++cnt;
    trie[cnt].initialize();
    return cnt;
}
void addWord(int p,char *s,int k)
{
    if(s[0]=='\0') return ;
    for(int i=0;s[i]!='\0';++i)
    {
        if(trie[p].next[mt[s[i]]]==-1)
        trie[p].next[mt[s[i]]]=getNewNode();
        p=trie[p].next[mt[s[i]]];
    }
    trie[p].v=k;
}
void init(int n)
{
    cnt=0;
    root=getNewNode();
    for(int i=1;i<=n;++i)
    {
        //gets(s);
        scanf("%s",s);
        addWord(root,s,1);
    }
}
void bfs(int p)
{
    trie[p].fail=root;
    queue<int>qt;
    qt.push(p);
    while(!qt.empty())
    {
        int y;
        int x=qt.front();qt.pop();
        for(int i=0;i<K;++i)
        if(trie[x].next[i]!=-1)
        {
            qt.push(trie[x].next[i]);
            if(x==root)
            {trie[trie[x].next[i]].fail=root;continue;}
            y=trie[x].fail;
            while(y!=root&&trie[y].next[i]==-1)
            y=trie[y].fail;
            if(trie[y].next[i]!=-1)
            trie[trie[x].next[i]].fail=trie[y].next[i];
            else
            trie[trie[x].next[i]].fail=root;
            trie[trie[x].next[i]].v|=trie[trie[trie[x].next[i]].fail].v;
        }
    }
}
void makeTo(int n,int k)
{
    for(int i=1;i<=n;++i)
    for(int j=0;j<k;++j)
    {
        int p=i;
        while(p!=root&&trie[p].next[j]==-1)
        p=trie[p].fail;
        if(trie[p].next[j]!=-1)
        to[i][j]=trie[p].next[j];
        else
        to[i][j]=root;
    }
};
int main()
{

    //freopen("data.in","r",stdin);
    mt.insert(pair<char,int>('A',0));
    mt.insert(pair<char,int>('C',1));
    mt.insert(pair<char,int>('G',2));
    mt.insert(pair<char,int>('T',3));
    int n;
    int ca=0;
    while(scanf("%d ",&n)!=EOF,n)
    {++ca;
        init(n);
        bfs(root);
        makeTo(cnt,K);
        //gets(s);
        scanf("%s",s);
        int m=strlen(s);
        memset(dp,-1,sizeof(dp));
        dp[0][1]=0;
        for(int i=0;i<m;++i)
        for(int j=1;j<=cnt;++j)
        if(dp[i][j]!=-1)
        {
            for(int w=0;w<K;++w)
            {
                int r=to[j][w];
                if(trie[r].v==1) continue;
                int tmp=(w==mt[s[i]])?0:1;
                if(dp[i+1][r]==-1||dp[i+1][r]>dp[i][j]+tmp)
                dp[i+1][r]=dp[i][j]+tmp;
                //cout<<(i+1)<<" "<<r<<" "<<dp[i+1][r]<<endl;
                //cout<<dp[i+1][r]<<endl;
            }
        }
        int ans=-1;
        for(int j=1;j<=cnt;++j)
        if(dp[m][j]!=-1)
        if(ans==-1||dp[m][j]<ans)
        ans=dp[m][j];
        printf("Case %d: %d\n",ca,ans);
    }
    return 0;
}