字典树

最新推荐文章于 2011-10-12 11:41:00 发布

原创最新推荐文章于 2011-10-12 11:41:00 发布 · 140 阅读

CC 4.0 BY-SA版权

本文介绍了一个解决HDU1251问题的字典树实现方案，包括字典树节点结构定义、插入操作及搜索操作的具体实现。通过C++代码示例，展示了如何构建字典树来存储字符串并查询特定字符串出现的次数。

HDU 1251 字典树

#include <iostream>
using namespace std;

const int kind = 26;

struct TreeNode
{
	int count;
	TreeNode *next[kind];

	TreeNode()
	{
		count = 1;
		for(int i = 0; i < kind; i++)
			next[i] = NULL;
	}
};


void Insert(TreeNode *&root, const char *word)
{
	TreeNode *p = root;
	int i, branch;
	i = branch = 0;

	if(NULL == p)
	{
		p = new TreeNode;
		root = p;
	}

	while(word[i])
	{
		branch = word[i] - 'a';
		if(p->next[branch])
			p->next[branch]->count++;
		else
			p->next[branch] = new TreeNode;

		i++;
		p = p->next[branch];
	}
}


int Search(TreeNode *&root, char *word)
{
	TreeNode *p = root;

	if(!p)
		return 0;

	int i, branch, ans;
	i = branch = ans = 0;

	while(word[i])
	{
		branch = word[i] - 'a';
		if(NULL == p->next[branch])
			return 0;
		ans = p->next[branch]->count;
		i++;
		p = p->next[branch];
	}
	return ans;
}


int main()
{

	char word[10], ask[10];
	TreeNode *root = NULL;
	while(gets(word))
	{
		if(word[0] == '\0')
			break;
		Insert(root, word);
	}

	while(gets(ask))
		cout<<Search(root, ask)<<endl;

	return 0;
}