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executable file
·98 lines (90 loc) · 2.63 KB
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/*
@filename 62.tireTree.cpp
@author caonan
@date 2022-05-01 15:24:43
@reference 剑指offer专项
@url https://leetcode-cn.com/problems/QC3q1f
@brief
Trie（发音类似 "try"）或者说 前缀树
是一种树形数据结构，用于高效地存储和检索字符串数据集中的键。这一数据结构有相当多的应用情景，例如自动补完和拼写检查。
请你实现 Trie 类：
Trie() 初始化前缀树对象。
void insert(String word) 向前缀树中插入字符串 word 。
boolean search(String word) 如果字符串 word 在前缀树中，返回 true（即，在检索之前已经插入）；否则，返回 false 。
boolean startsWith(String prefix) 如果之前已经插入的字符串 word 的前缀之一为 prefix ，返回 true ；否则，返回 false 。
*/
#include <assert.h>
#include <stdio.h>
#include <algorithm>
#include <bitset>
#include <deque>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <unordered_map>
#include <unordered_set>
#include <vector>
using namespace std;
class Trie
{
public:
/** Initialize your data structure here. */
Trie() : root_(new tire_node()) {}
/** Inserts a word into the trie. */
void insert(string word)
{
auto it = root_;
for (auto c : word) {
if (!it->tire_nodes[c - 'a']) {
it->tire_nodes[c - 'a'] = new tire_node();
}
it = it->tire_nodes[c - 'a'];
}
it->isTail = true;
}
/** Returns if the word is in the trie. */
bool search(string word)
{
auto it = root_;
for (auto c : word) {
if (!it->tire_nodes[c - 'a']) return false;
it = it->tire_nodes[c - 'a'];
}
return it->isTail;
}
/** Returns if there is any word in the trie that starts with the given prefix. */
bool startsWith(string prefix)
{
auto it = root_;
for (auto c : prefix) {
if (!it->tire_nodes[c - 'a']) return false;
it = it->tire_nodes[c - 'a'];
}
return true;
}
private:
struct tire_node {
tire_node() : tire_nodes(26, nullptr), isTail(false) {}
bool isTail;
vector<tire_node*> tire_nodes;
};
tire_node* root_;
};
/**
* Your Trie object will be instantiated and called as such:
* Trie* obj = new Trie();
* obj->insert(word);
* bool param_2 = obj->search(word);
* bool param_3 = obj->startsWith(prefix);
*/
int main()
{
Trie* obj = new Trie();
obj->insert("hello");
assert(obj->search("hello"));
assert(obj->startsWith("hel"));
return 0;
}