HDU-2072-单词数(字典树)

链接:

https://vjudge.net/problem/HDU-2072

题意:

lily的好朋友xiaoou333最近很空，他想了一件没有什么意义的事情，就是统计一篇文章里不同单词的总数。下面你的任务是帮助xiaoou333解决这个问题。

思路:

字典树, 插入的时候判断是否为重复插入即可.

代码:

#include <iostream>
#include <cstdio>
#include <cstring>
#include <vector>
//#include <memory.h>
#include <queue>
#include <set>
#include <map>
#include <algorithm>
#include <math.h>
#include <stack>
#include <string>
#include <assert.h>
#include <iomanip>
#include <iostream>
#include <sstream>
#define MINF 0x3f3f3f3f
using namespace std;
typedef long long LL;
const int INF = 1e9;
const int MAXN = 1e6+10;

int cnt, n;
string word;

struct Node
{
    bool Ends;
    int Next[30];
    void Init()
    {
        Ends = false;
        memset(Next, 0, sizeof(Next));
    }
}Trie[MAXN];

bool Insert(string val)
{
    int root = 0;
    int len = val.size();
    for (int i = 0;i < len;i++)
    {
        if (Trie[root].Next[val[i]-'a'] == 0)
        {
            Trie[root].Next[val[i]-'a'] = ++cnt;
            Trie[cnt].Init();
        }
        root = Trie[root].Next[val[i]-'a'];
    }
    if (Trie[root].Ends)
        return false;
    Trie[root].Ends = true;
    return true;
}

int main()
{
    while (getline(cin, word))
    {
        if (word[0] == '#')
            break;
        cnt = 0;
        int ans = 0;
        Trie[0].Init();
        stringstream ss(word);
        while (ss >> word)
        {
            if (Insert(word))
                ans++;
        }
        printf("%d\n", ans);
        for (int i = 0;i <= cnt;i++)
            Trie[i].Init();
    }

    return 0;
}