POJ 2418 Hardwood Species（字典树）

/*
** POJ 2418 Hardwood Species
** Created by Rayn @@ 2014/05/01
** Trie树
*/
#include <cstdio>
#include <cstring>
#include <cstdlib>

const int ChildSize = 256;

int tot;

struct TrieNode {
int val;  /* 用于记录单词出现的次数*/
TrieNode *child[ChildSize]; /* 分支节点的孩子指针 */
};
TrieNode *InitTrie()
{
return (TrieNode*)calloc(1, sizeof(TrieNode));
}
void Insert(TrieNode *root, char *word)
{
TrieNode *now = root;

for(char *p=word; *p; p++)
{
int v = *p;
if(now->child[v] == 0)
{
now->child[v] = (TrieNode*)calloc(1, sizeof(TrieNode));
}
now = now->child[v];
}
//到达记录统计单词次数的节点
now->val++;
}
void Search(TrieNode *root)
{
static char tmp[31];
static int pos;

if(root->val)
{
tmp[pos] = '\0';
if(tmp[0])
{
printf("%s %.4f\n", tmp, (root->val*100.0)/tot);
}
}
for(int i=0; i<256; ++i)
{
if(root->child[i])
{
tmp[pos] = i;
pos++;
Search(root->child[i]);
pos--;  //回溯
}
}
}
int main()
{
char word[31];
TrieNode *root;

tot = 0;
root = InitTrie();
while(gets(word))
{
Insert(root, word);
tot++;
}
Search(root);
return 0;
}