HDU 5687 字典树插入查找删除

时间:2023-03-08 19:14:11

题目:http://acm.hdu.edu.cn/showproblem.php?pid=5687

2016百度之星资格赛C题,直接套用字典树,顺便巩固了一下自己对字典树的理解

 #include<stdio.h>
#include<string.h>
struct node{
int next[];
int cnt;
void init(){
cnt = ;//计数
memset(next,-,sizeof(next));
}
};
struct node trie[];
int tot = ;//记录节点数 void insert(char *s){
int cur = ,len = strlen(s);
for(int i = ;i<len;i++){
int temp = s[i]-'a';
int next = trie[cur].next[temp];
if(next == -){
next = ++tot;
trie[next].init();
trie[cur].next[temp] = next;
}
cur = next;
trie[cur].cnt++;
}
}
int find(char *s){
int cur = ,len = strlen(s);
for(int i = ;i<len;i++){
int temp = s[i]-'a';
int next = trie[cur].next[temp];
if(next == -)
return ;
cur = next;
}
return trie[cur].cnt>;//注意
}
void del(char *s){
int cur = ,late,len = strlen(s);
//这里特判一下要删除的字符串是否存在
for(int i=;i<len;i++){
int tmp=s[i]-'a';
int next=trie[cur].next[tmp];
if(next==-) return;
late = cur;
cur=next;
}
cur = ;
for(int i = ;i<len;i++){
int temp = s[i]-'a';
int next = trie[cur].next[temp];
late = cur;
cur = next;
trie[cur].cnt--;
}
trie[cur].init();
int temp = s[len-]-'a';
trie[late].next[temp] = -;
}
int main(){
int n;
scanf("%d",&n);
char op[],s[];
trie[].init();
while(n--){
scanf(" %s %s",op,s);
if(op[] == 'i'){
insert(s);
}else if(op[] == 's'){
if(find(s))
puts("Yes");
else
puts("No");
}else{
del(s);
}
}
return ;
}