模板
Trie字典树大致可以分为两种实现方式，一种是数组，另一种是指针，那么我们就整理了两个模板：
数组的实现：
#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <map>
using namespace std;
const int N = 1000000;
int ch[N][26],val[N],tot;
//数组实现的话，总是拿不准ch数组的大小，我们不确定生成的节点会有多少
void Init()
{
memset(ch[0],0,sizeof(ch[0]));
tot = 1;
memset(val,0,sizeof(val));
}
void Insert(char *s,int x)
{
int u = 0,len = strlen(s);
for(int i =0 ;i < len;i ++)
{
int v = s[i]-'a';
if(!ch[u][v])
{
memset(ch[tot],0,sizeof(ch[tot]));
val[tot] = 0;
ch[u][v] = tot ++;
}
u = ch[u][v];
}
val[u] = x;//结尾位置设置为权重，其余位置都设置为0
}
int Find(char *s)
{
int u = 0,len = strlen(s);
for(int i =0;i < len;i ++)
{
int v = s[i]-'a';
if(!ch[u][v]) return 0;
u = ch[u][v];
}
return val[u];
}
void Del(char *s)
{
int u = 0,len = strlen(s);
for(int i =0 ;i < len;i ++)
{
int v = s[i] - 'a';
if(!ch[u][v]) return ;
u = ch[u][v];
}
val[u] = 0;//删除时就是将最后一个位置的权值设置为0
}
指针实现
#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <map>
using namespace std;
//指针实现较为方便，并且也很容易理解
struct Trie
{
Trie *next[26];
int val;
};
Trie *root;
void Init()
{
root = (Trie *)malloc(sizeof(Trie));
for(int i = 0;i < 26;i ++)
root->next[i] = NULL;
root->val = 0;
}
void Insert(char *s)
{
Trie *p = root,*q;
int len = strlen(s);
for(int i = 0;i < len;i ++)
{
int v = s[i] - 'a';
if(p->next[v] == NULL)
{
q = (Trie *)malloc(sizeof(Trie));
q->val = 0;
for(int j = 0;j < 26;j ++)
q->next[j] = NULL;
p->next[v] = q;
}
p = p->next[v];
}
p->val = 1;
}
int Find(char *s)
{
int len = strlen(s);
Trie *p = root;
for(int i =0 ;i < len;i ++)
{
int v = s[i] - 'a';
p = p->next[v];
if(p == NULL) return -1;
}
return p->val;
}
void Del(Trie *s)
{
if(s == NULL)
return ;
for(int i =0;i < 26;i ++)
if(s->next[i])
Del(s->next[i]);
delete s;
}
栗子
#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#include<cmath>
using namespace std;
const int N = 1000000;
int sz;
int ch[N][26];
int val[N];
struct Trie
{
Trie(){
sz = 1;//这里要把0节点空出来，作为全部的根节点
memset(ch[0],0,sizeof(ch[0]));
memset(val,0,sizeof(val));
}
int idx(char c)
{
return c-'a';
}
void Insert(char *s,int v)
{
int u = 0,len = strlen(s);
for(int i =0 ;i < len;i ++)
{
int c = idx(s[i]);
if(!ch[u][c])//表示这个节点重新作为一个新的节点，下面仍然还有26个子节点
{
memset(ch[sz],0,sizeof(ch[sz]));
val[sz] = 0;
ch[u][c] = sz++;
}
u = ch[u][c];
val[u] ++;
}
}
int Read(char *s)
{
int u = 0,len = strlen(s);
for(int i = 0;i < len;i ++)
{
int c = idx(s[i]);
if(!ch[u][c]) return -1;
else u = ch[u][c];
}
if(val[u] == 0)
return 1;
else
return 2;
}
int Get_num(char *s)
{
int u = 0,len = strlen(s);
for(int i = 0;i < len;i ++)
{
int c = idx(s[i]);
if(!ch[u][c]) return 0;
else u = ch[u][c];
}
return val[u];
}
};
int main()
{
Trie T;
char s[15];
while(1)
{
gets(s);
if(s[0] == '\0') break;
T.Insert(s,1);
}
while(gets(s))
{
printf("%d\n",T.Get_num(s));
}
return 0;
}
#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <map>
using namespace std;
struct Trie
{
Trie *next[26];
char *val;
};
Trie *root;
void Init()
{
root = (Trie *)malloc(sizeof(Trie));
for(int i = 0;i < 26;i ++)
root->next[i] = NULL;
root->val = NULL;
}
void Insert(char *s,char *str)
{
Trie *p = root,*q;
int len = strlen(s);
for(int i = 0;i < len;i ++)
{
int v = s[i] - 'a';
if(p->next[v] == NULL)
{
q = (Trie *)malloc(sizeof(Trie));
q->val = NULL;
for(int j = 0;j < 26;j ++)
q->next[j] = NULL;
p->next[v] = q;
}
p = p->next[v];
}
p->val = new char[11];
strcpy(p->val,str);
}
void Find(char *s)
{
int len = strlen(s);
Trie *p = root;
for(int i =0 ;i < len;i ++)
{
int v = s[i] - 'a';
p = p->next[v];
if(p == NULL) {printf("%s",s);return ;}
}
if(p->val) printf("%s",p->val);
else printf("%s",s);
}
void Del(Trie *s)
{
if(s == NULL)
return ;
for(int i =0 ;i < 26;i ++)
{
if(s->next[i])
Del(s->next[i]);
}
delete s->val;
delete s;
}
int main()
{
char s[15],s1[15];
Init();
scanf("%s",s);
while(scanf("%s %s\n",s,s1) && strcmp(s,"END"))
{
Insert(s1,s);
}
char str[3100],part[100];
while(gets(str) && strcmp(str,"END"))
{
int index = 0;
int len = strlen(str);
for(int i = 0;i < len;i ++)
{
if(islower(str[i]))
part[index++] = str[i];
else
{
part[index] = '\0';
Find(part);
index = 0;
printf("%c",str[i]);
}
}
puts("");
}
}
参考博客
https://blog.csdn.net/hcbbt/article/details/39499325