字典树思路

用字典树搞一下就好了，比如aaaaa ：   a存5次 aa 4次以此类推～

字典树板子复习：P8306 【模板】字典树

这里这个清空方式 很好 因为很多时候memset   T

#include<iostream>
#include<cstring>
using namespace std;


const int N = 3e6+10;
int n,m;
string s;
int tire[N][70],cnt[N],idx;


void insert(){
	int p = 0;
	for(auto &t:s){
		int u;
		if(t>='a'&&t<='z')u = t-'a';
		else if(t>='A'&&t<='Z')u = t-'A'+ 27;
		else u = t -'0'+54;
		if(!tire[p][u]) tire[p][u]=++idx;
		p = tire[p][u];	
		cnt[p]++;
	}
}

int query(){
	int p=0;
	for(auto &t:s){
		int u;
		if(t>='a'&&t<='z')u = t-'a';
		else if(t>='A'&&t<='Z')u = t-'A'+ 27;
		else u = t -'0'+54;
		if(!tire[p][u]) return 0;
		p = tire[p][u];
	}
	
	return cnt[p];
}





void solve()
{
	cin>>n>>m;
	
	for(int i=0;i<=idx;i++)
	 for(int j=0;j<=65;j++)
	  tire[i][j] = 0;
	  
	for(int i=0;i<=idx;i++)cnt[i] = 0;
	idx = 0;
	while(n--)
	{
		cin>>s;insert();
	}
	
	while(m--){
		cin>>s;cout<<query()<<"\n";
	}
}


int main()
{
	int _;cin>>_;
	while(_--)solve();
}

本题代码;

const int N = 5e5+10;
int tr[N][27],cnt[N],idx;
class Solution {
public:

    string str;
    void insert(){
    	int ts = str.size();
        int p = 0;
        for(auto &t:str){
            int u = t - 'a';
            if(!tr[p][u])tr[p][u] = ++idx;
            p = tr[p][u];
            cnt[p]+=ts--;
        }

    }

    int find(char c){ 
        int p = 0;
        int t = 0;
        int u = c-'a';
        while(cnt[tr[p][u]]>=3){
        	t++;
        	p = tr[p][u];
        }
        return t;
    }

    int maximumLength(string s) {
        for(int i=0;i<=idx;i++)
         for(int j=0;j<=26;j++)
          tr[i][j] = 0;
        for(int i=0;i<=idx;i++)cnt[i] = 0;
        idx = 0;
        char c = s[0];
        int t = 1;
        for(int i=1;i<s.size();i++){
            if(s[i]!=c){
                str = "";
                while(t--)str+=c;
                insert();
                cout<<str<<"\n";
                c = s[i];
                t = 1;
            }else t++;
        }

        str = "";
        while(t--)str+=c;
        insert();
        cout<<str<<"\n";
        int ans = 0;
        for(char i='a';i<='z';i++) 
         ans = max(ans,find(i));
        if(ans)return ans;
        return -1;

    }
};