trie树
class Trie {
public:
/** Initialize your data structure here. */
Trie() {
memset(son, 0, sizeof(son));
memset(count, 0, sizeof(count));
idx = 0;
}
/** Inserts a word into the trie. */
void insert(string word) {
int p = 0, u = 0;
for(int i = 0; i < word.length(); i++){
u = word[i] - 'a';
if(!son[p][u]) son[p][u] = ++idx;
p = son[p][u];
}
count[p]++;
}
/** Returns if the word is in the trie. */
bool search(string word) {
int p = 0, u = 0;
for(int i = 0; i < word.length(); i++){
u = word[i] - 'a';
if(!son[p][u]){
return false;
}
p = son[p][u];
}
if(count[p]) return true;
return false;
}
/** Returns if there is any word in the trie that starts with the given prefix. */
bool startsWith(string prefix) {
int p = 0, u = 0;
for(int i = 0; i < prefix.length(); i++){
u = prefix[i] - 'a';
if(!son[p][u]) {
return false;
}
p = son[p][u];
}
return true;
}
private:
static const int maxn = 1e5+8;
int son[maxn][26];
int count[maxn];
int idx = 0;
};