【字符串】AC自动机

最新推荐文章于 2024-05-02 23:37:28 发布

原创最新推荐文章于 2024-05-02 23:37:28 发布 · 250 阅读

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HDU3065(初始化更新很省时间)

#include<bits/stdc++.h>
#pragma GCC optimize(2)
#define ll long long
#define rep(i,a,n) for(int i=a;i<=n;i++)
#define per(i,n,a) for(int i=n;i>=a;i--)
#define endl '\n'
#define eps 0.000000001
#define pb push_back
#define mem(a,b) memset(a,b,sizeof(a))
#define IO ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
const int INF=0x3f3f3f3f;
const ll inf=0x3f3f3f3f3f3f3f3f;
const int mod=1e9+7;
const int maxn=5e4+100;

int tree[maxn][30]; 
int num[maxn];
int fail[maxn];int ans[1005];
int tot = 0,n;
string s[1005];
void init(){
	mem(ans,0);tot=0;
	mem(tree[0],0);
	fail[0]=num[0]=0;
}
void insert_(string s,int t){
    int root = 0;
    for(int i=0;i<s.length();i++){
        int id=s[i]-'A';
        if(!tree[root][id]){
            tree[root][id]=++tot;
    		mem(tree[tree[root][id]],0);
    		fail[tree[root][id]]=0;
    		num[tree[root][id]]=0;
		}
		root=tree[root][id];
    }
	num[root]=t;
}
void getFail(){
    queue <int>q;
    for(int i=0;i<26;i++){
        if(tree[0][i]){
            fail[tree[0][i]] = 0;
            q.push(tree[0][i]);
        }
    }
    while(!q.empty()){
        int now = q.front();
        q.pop();
        for(int i=0;i<26;i++){
            if(tree[now][i]){
                fail[tree[now][i]] = tree[fail[now]][i];
                q.push(tree[now][i]);
            }
            else
                tree[now][i] = tree[fail[now]][i];
        }
    }
}

void query(string S){
    int now = 0,maxx=0;
    for(int i=0;i<S.length();i++){
    	if(S[i]<'A'||S[i]>'Z') {now=0;continue;}
        now = tree[now][S[i]-'A'];
        for(int j=now;j;j=fail[j]){
			ans[num[j]]++;
	    }
    }
	rep(i,1,n){
		if(ans[i]){
			cout<<s[i]<<": "<<ans[i]<<endl;
		}
	}
}

int main(){
	IO;
	while(cin>>n){
		init();
		rep(i,1,n){
			cin>>s[i];
			insert_(s[i],i);
		}
		fail[0]=0;
		getFail();
		string a;
		cin>>a;
		query(a);
	}
}

面向对象封装版本：

#include<bits/stdc++.h>
#pragma GCC optimize(2)
#define ll long long
#define rep(i,a,n) for(int i=a;i<=n;i++)
#define per(i,n,a) for(int i=n;i>=a;i--)
#define endl '\n'
#define eps 0.000000001
#define pb push_back
#define mem(a,b) memset(a,b,sizeof(a))
#define IO ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
const int INF=0x3f3f3f3f;
const ll inf=0x3f3f3f3f3f3f3f3f;
const int mod=1e9+7;
string s[1005];int n;
class ac_auto{
	public:
		const static int maxn=5e4+100;
		int tot,root;
		int tree[maxn][30]; 
		int End[maxn];
		int fail[maxn];int ans[1005];
		int newnode(){
			for(int i=0;i<26;i++){
				tree[tot][i]=0;
			}
			End[tot]=0;
			return tot++;
		}
		void init(){
			mem(ans,0);tot=0;
			root=newnode();
		}				
		void insert_(string s,int t){
		    int now = root;
		    for(int i=0;i<s.length();i++){
		        int id=s[i]-'A';
		        if(!tree[now][id]){
		            tree[now][id]=newnode();
				}
				now=tree[now][id];
		    }
			End[now]=t;
		}
		
		void getFail(){
		    queue <int>q;
		    for(int i=0;i<26;i++){
		        if(tree[0][i]){
		            fail[tree[0][i]] = 0;
		            q.push(tree[0][i]);
		        }
		    }
		    while(!q.empty()){
		        int now = q.front();
		        q.pop();
		        for(int i=0;i<26;i++){
		            if(tree[now][i]){
		                fail[tree[now][i]] = tree[fail[now]][i];
		                q.push(tree[now][i]);
		            }
		            else
		                tree[now][i] = tree[fail[now]][i];
		        }
		    }
		}	
		
		void query(string S){
		    int now = root;
		    for(int i=0;i<S.length();i++){
		    	if(S[i]<'A'||S[i]>'Z') {now=0;continue;}
		        now = tree[now][S[i]-'A'];
		        for(int j=now;j;j=fail[j]){
					ans[End[j]]++;
			    }
		    }
			for(int i=1;i<=n;i++){
				if(ans[i]){
					cout<<s[i]<<": "<<ans[i]<<endl;
				}
			}		    
		}
}acam;
int main(){
	IO;
	while(cin>>n){
		acam.init();
		rep(i,1,n){
			cin>>s[i];
			acam.insert_(s[i],i);
		}
		acam.getFail();
		string a;
		cin>>a;
		acam.query(a);
		
	}
}

模板洛谷P3808：

#include<bits/stdc++.h>
#pragma GCC optimize(2)
#define ll long long
#define rep(i,a,n) for(int i=a;i<=n;i++)
#define per(i,n,a) for(int i=n;i>=a;i--)
#define endl '\n'
#define eps 0.000000001
#define pb push_back
#define mem(a,b) memset(a,b,sizeof(a))
#define IO ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
const int INF=0x3f3f3f3f;
const ll inf=0x3f3f3f3f3f3f3f3f;
const int mod=1e9+7;
const int maxn = 2*1e6+9;

int tree[maxn][26]; 
int cntword[maxn];
int fail[maxn];
int tot = 0;

void insert_(string s){
    int root = 0;
    for(int i=0;i<s.size();i++){
        int id=s[i]-'a';
        if(!tree[root][id])
            tree[root][id]=++tot;
        root=tree[root][id];
    }
    cntword[root]++;
}
void getFail(){
    queue <int>q;
    for(int i=0;i<26;i++){
        if(tree[0][i]){
            fail[tree[0][i]] = 0;
            q.push(tree[0][i]);
        }
    }
    while(!q.empty()){
        int now = q.front();
        q.pop();
        for(int i=0;i<26;i++){
            if(tree[now][i]){
                fail[tree[now][i]] = tree[fail[now]][i];
                q.push(tree[now][i]);
            }
            else
                tree[now][i] = tree[fail[now]][i];
        }
    }
}


int query(string s){
    int now = 0,ans = 0;
    for(int i=0;i<s.size();i++){
        now = tree[now][s[i]-'a'];
        for(int j=now;j && cntword[j]!=-1;j=fail[j]){
            ans += cntword[j];
            cntword[j] = -1;
        }
    }
    return ans;
}

int main() {
    int n;
    string s;
    cin >> n;
    for(int i=0;i<n;i++){
        cin >> s ;
        insert_(s);
    }
    fail[0] = 0;
    getFail();
    cin >> s ;
    cout << query(s) << endl;
    return 0;
}

在这里插入图片描述

#include<bits/stdc++.h>
#define ll long long
#define rep(i,a,n) for(int i=a;i<=n;i++)
#define per(i,n,a) for(int i=n;i>=a;i--)
#define endl '\n'
#define eps 0.000000001
#define pb push_back
#define mem(a,b) memset(a,b,sizeof(a))
#define IO ios::sync_with_stdio(false);cin.tie(0);
using namespace std;
const int INF=0x3f3f3f3f;
const ll inf=0x3f3f3f3f3f3f3f3f;
const int mod=1e9+7;
const int maxn=2e5+5;

int tree[maxn][26]; 
int match[maxn];
int fail[maxn];
int flag[maxn];
int tot = 0;

void insert_(string s,int t){
    int root=0;
    for(int i=0;i<s.length();i++){
        int id=s[i]-'a';
        if(!tree[root][id])
            tree[root][id]=++tot;
        root=tree[root][id];
    }
    if(!flag[root]) flag[root]=t;
	match[t]=flag[root];
}
int indeg[maxn],ans[maxn];
void getFail(){
    queue <int>q;
    for(int i=0;i<26;i++){
        if(tree[0][i]){
            fail[tree[0][i]] = 0;
            q.push(tree[0][i]);
        }
    }
    while(!q.empty()){
        int now = q.front();
        q.pop();
        for(int i=0;i<26;i++){
            if(tree[now][i]){
                fail[tree[now][i]] = tree[fail[now]][i];
                indeg[fail[tree[now][i]]]++;
                q.push(tree[now][i]);
            }
            else
                tree[now][i] = tree[fail[now]][i];
        }
    }
}
string ss[maxn];
int n,vis[maxn];
void query(string s){
    int now = 0;
    for(int i=0;i<s.length();i++){
        now = tree[now][s[i]-'a'];
		ans[now]++;
    }
}
void topusort(){
	queue<int> q;
	rep(i,1,tot){
		if(!indeg[i]) q.push(i);
	}
	while(!q.empty()){
		int u=q.front();q.pop();
		vis[flag[u]]=ans[u];
		int v=fail[u];
		ans[v]+=ans[u];
		if(--indeg[v]==0) q.push(v);		
	}
}
int main(){
	cin>>n;
	rep(i,1,n){
		cin>>ss[i];
		insert_(ss[i],i);
	}
	getFail();
	string s;cin>>s;
	query(s);
	topusort();
	rep(i,1,n){
		cout<<vis[match[i]]<<endl;
	}
}