杭电2072 单词数(Trie tree或者STL)

->题目请戳这里<-

题目大意：中文题，不解释。

题目分析：字典树水过~

详情请见代码：

#include <iostream>
#include<cstdio>
#include<map>
#include<string>
#include<cstring>
#include<cstdlib>
#include<set>

using namespace std;
typedef struct node
{
    struct node *next[26];
    int end;
}tree;
char s[100005];
int len;
int deep;
int cnt;

void init(tree *t)
{
    t->end = 0;
    int i;
    for(i = 0;i < 26;i ++)
        t->next[i] = NULL;
}

void del(tree *t)
{
    int i;
    for(i = 0;i < 26;i ++)
        if(t->next[i] != NULL)
            del(t->next[i]);
    free(t);
}

void build(tree *t,int id)
{
    if(t->next[s[id] - 'a'] == NULL)
    {
        t->next[s[id] - 'a'] = (tree *)malloc(sizeof(tree));
        init(t->next[s[id] - 'a']);
    }
    if(s[id + 1] == ' ' || s[id + 1] == '\0')
    {
        if(t->next[s[id] - 'a']->end == 0)
        {
            t->next[s[id] - 'a']->end = 1;
            cnt ++;
        }
        deep = id + 1;
        return;
    }
    else
        build(t->next[s[id] - 'a'],id + 1);
}

int main()
{
    int i;
    tree *root = NULL;
    while(gets(s) && strcmp(s,"#") != 0)
    {
        cnt = 0;
        root = (tree *)malloc(sizeof(tree));
        init(root);
        len = strlen(s);
        int flag;
        for(i = 0;i < len;i ++)
        {
            if(s[i] == ' ')
            {
                while(s[i] == ' ')
                    i ++;
                i --;
            }
            else
            {
                deep = 0;
                build(root,i);
               // printf("deep:%d\n",deep);
                i = (deep - 1);
            }
        }
        printf("%d\n",cnt);
        del(root);
    }
    return 0;
}
//0MS	332K

这题数据应该很弱，字典树竟然只花了332K。。。

其实此题还有更简单解法，可以用STL的set水过~

详情请见代码：

#include <iostream>
#include<cstdio>
#include<map>
#include<string>
#include<cstring>
#include<cstdlib>
#include<set>

using namespace std;

set<string> lcm;
string s;
char str[100005];
char tmp[100005];
int main()
{
    int i,j;

    while(gets(str),strcmp(str,"#") != 0)
    {
        lcm.clear();
        i = 0;
        while(str[i] == ' ')
            i ++;
        j = 0;
        //printf("len:%d\ni:%d\n",strlen(str),i);
        for(;i < strlen(str);i ++)
        {
            if(str[i] == ' ')
            {
                tmp[j] = '\0';
                s = tmp;
                lcm.insert(s);
                j = 0;
                while(str[i] == ' ')
                    i ++;
                i --;
            }
            else
                tmp[j ++] = str[i];
        }
        if(j)
        {
            s = tmp;
            lcm.insert(s);
        }
        printf("%d\n",lcm.size());
    }
    return 0;
}
//0MS	364K