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  • hdu 2846(字典树)

    Repository

    Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
    Total Submission(s): 5048    Accepted Submission(s): 1739

    Problem Description
    When you go shopping, you can search in repository for avalible merchandises by the computers and internet. First you give the search system a name about something, then the system responds with the results. Now you are given a lot merchandise names in repository and some queries, and required to simulate the process.
    Input
    There is only one case. First there is an integer P (1<=P<=10000)representing the number of the merchanidse names in the repository. The next P lines each contain a string (it's length isn't beyond 20,and all the letters are lowercase).Then there is an integer Q(1<=Q<=100000) representing the number of the queries. The next Q lines each contains a string(the same limitation as foregoing descriptions) as the searching condition.
    Output
    For each query, you just output the number of the merchandises, whose names contain the search string as their substrings.
    Sample Input
    20
    ae
    af
    ag
    ah
    ai
    aj
    ak
    al
    ads
    add
    ade
    adf
    adg
    adh
    adi
    adj
    adk
    adl
    aes
    5
    b
    a
    d
    ad
    s
    Sample Output
    0
    20
    11
    11
    2
    我好气呀 g++无限爆内存 换c++过了 无奈下顺便写了个静态的
    题意就是有n个字符串,m个询问  问字符串在n个字符串中出现过多少次
    比如 abcd 中有a,b,c,d,abcd,bcd,cd,bc,abc...
    我们可以将abcd拆成abcd bcd cd d 分别建树,每个字符计算下数字
    但abab会导致重复,所以我们设置一下标记,看代码
    动态建树,g++爆内存  c++交
     1 #include<iostream>
     2 #include<cstdio>
     3 #include<cmath>
     4 #include<cstring>
     5 #include<algorithm>
     6 #include<queue>
     7 #include<map>
     8 #include<set>
     9 #include<vector>
    10 #include<cstdlib>
    11 #include<string>
    12 #define eps 0.000000001
    13 typedef long long ll;
    14 typedef unsigned long long LL;
    15 using namespace std;
    16 struct tire{
    17     int id,num;
    18     tire *next[26];
    19 };
    20 tire *root;
    21 void insert(char *s,int k){
    22     tire *p,*q;
    23     p=root;
    24     int len=strlen(s);
    25     for(int i=0;i<len;i++){
    26         //cout<<3<<endl;
    27         int t=s[i]-'a';
    28         if(p->next[t]==NULL){
    29             q=(tire *)malloc(sizeof(tire));
    30             for(int j=0;j<26;j++)q->next[j]=NULL;
    31             q->num=0;
    32             q->id=-1;
    33             p->next[t]=q;
    34         }
    35         p=p->next[t];
    36         if(p->id!=k){
    37             p->id=k;
    38             p->num++;
    39         }
    40     }
    41 }
    42 int find(char *s){
    43     tire *p=root;
    44     int len=strlen(s);
    45     for(int i=0;i<len;i++){
    46         int t=s[i]-'a';
    47         if(p->next[t]==NULL)return 0;
    48         else
    49             p=p->next[t];
    50     }
    51     return p->num;
    52 }
    53 int main(){
    54     int m,n;
    55     char str[22];
    56     root=(tire *)malloc(sizeof(tire));
    57     for(int i=0;i<26;i++)root->next[i]=NULL;
    58     root->id=-1;
    59     root->num=0;
    60     scanf("%d",&n);
    61     for(int i=0;i<n;i++){
    62         scanf("%s",str);
    63         int len=strlen(str);
    64         for(int j=0;j<len;j++){
    65             //cout<<1<<endl;
    66             insert(str+j,i);//cout<<2<<endl;
    67         }
    68     }
    69     scanf("%d",&m);
    70     while(m--){
    71         scanf("%s",str);
    72         cout<<find(str)<<endl;
    73     }
    74 }

    接下来是一个静态的字典树(节省内存) c++ g++都可以过

    #include<iostream>
    #include<cstdio>
    #include<cmath>
    #include<cstring>
    #include<algorithm>
    #include<queue>
    #include<map>
    #include<set>
    #include<vector>
    #include<cstdlib>
    #include<string>
    #define maxnode 500000
    #define sigma_size 30
    #define eps 0.000000001
    typedef long long ll;
    typedef unsigned long long LL;
    using namespace std;
    int ch[maxnode][sigma_size];
    int val[maxnode];
    int flag[maxnode];
    int sz;
    void init(){
        memset(ch[0],0,sizeof(ch[0]));
        sz=1;
    }
    int idx(char c){
        return c-'a';
    }
    void insert(char *s,int k){
        int u=0;
        int len=strlen(s);
        for(int i=0;i<len;i++){
            int c=idx(s[i]);
            if(ch[u][c]==0){
               memset(ch[sz],0,sizeof(ch[sz]));
               val[sz]=0;
               ch[u][c]=sz++;
            }
            u=ch[u][c];
            if(flag[u]!=k){
                val[u]++;
                flag[u]=k;
            }
        }
    }
    int find(char *s){
        int u=0;
        int len=strlen(s);
        for(int i=0;i<len;i++){
            int c=idx(s[i]);
            if(ch[u][c]==0)return 0;
            u=ch[u][c];
        }
        return val[u];
    }
    int main(){
        int m,n;
        init();
        memset(flag,-1,sizeof(flag));
        //for(int i=0;i<10;i++)cout<<flag[i]<<" ";
        char str[100];
        scanf("%d",&n);
        for(int i=0;i<n;i++){
            scanf("%s",str);
            int len=strlen(str);
            for(int j=0;j<len;j++){
                //cout<<1<<endl;
                insert(str+j,i);//cout<<2<<endl;
            }
        }
        scanf("%d",&m);
        while(m--){
            scanf("%s",str);
            cout<<find(str)<<endl;
        }
    }
    Source
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  • 原文地址:https://www.cnblogs.com/Aa1039510121/p/6413613.html
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