动态开点

#include <iostream>
#include <algorithm>
#include <cstring>
#include <cstdio>
#include <cstdlib>
using namespace std;
struct node
{int val;struct node *next[26];
}*head;
void Insert(char *s)
{struct node *pp=head;for(;*s;s++){int id=*s-'a';if(pp->next[id]==NULL){pp->next[id]=(struct node*)malloc(sizeof(struct node));pp->next[id]->val=0;for(int i=0;i<26;i++)pp->next[id]->next[i]=NULL;}pp=pp->next[id];pp->val++;}
}
int Search(char *s)
{
//    struct node *pp=(struct node*)malloc(sizeof(struct node));
//    pp=head;   不要重新申请内存，浪费内存   ＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊＊struct node *pp=head;for(;*s;s++){int id=*s-'a';if(pp->next[id]==NULL)return 0;pp=pp->next[id];}if(pp->val)return 1;return 0;
}
void DDDD(struct node *pp)
{for(int i=0;i<26;i++){if(pp->next[i]!=NULL)DDDD(pp->next[i]);pp->next[i]=NULL;}pp=NULL;
}
void Delete(char *s)
{struct node *pp=head;int num=0;int len=strlen(s);for(int i=0;i<len;i++){int id=s[i]-'a';if(pp->next[id]==NULL)return;pp=pp->next[id];num=pp->val;}pp=head;for(int i=0;i<len;i++){int id=s[i]-'a';pp=pp->next[id];pp->val=pp->val-num;}DDDD(pp);
}
int main()
{int n;scanf("%d",&n);head=(struct node*)malloc(sizeof(struct node));head->val=0;for(int i=0;i<26;i++)head->next[i]=NULL;while(n--){char s1[10],s2[35];scanf("%s%s",s1,s2);if(s1[0]=='i')Insert(s2);else if(s1[0]=='s')printf(Search(s2)?"Yes\n":"No\n");else if(s1[0]=='d')Delete(s2);}
}

静态

#include <iostream>
#include <algorithm>
#include <string>
#include <cstring>
#include <map>
using namespace std;
const int N =1e5*26;
int ch[N][26],tot=1,cnt[N];
void Insert(char *s)
{cnt[1]++;for(int p=1;*s;s++){int t=*s-'a';cnt[p]++;if(!ch[p][t]){ch[p][t]=++ tot;}cnt[p=ch[p][t]]++;}
}int Search(char *s)
{int p=1;while(*s&&p){int t=*(s++)-'a';if(cnt[p])p=ch[p][t];else p=0;}return p;
}
void Delete(char *s)
{int x=cnt[Search(s)];if(!x) return;int p = 1;while(*s&&p){int t=*(s++)-'a';cnt[p]-=x;if(cnt[ch[p][t]]==x){ch[p][t]=0;}p=ch[p][t];}
}int main()
{int n;scanf("%d",&n);char a[10],b[31];for(int i=0;i<n;i++){scanf("%s%s",a,b);if(a[0]=='i')Insert(b);else if(a[0] == 'd')Delete(b);elseputs(Search(b)?"Yes":"No");}
}