poj 2418 bst统计字符串

数据比较随机，直接bst可以过。

#include <cstring>
#include <cstdio>
using namespace std;

const int N = 101;
int tot;

struct Node 
{
    Node * ch[2];
    char v[N];    
    int cnt;
    int cmp( char * x )
    {
        int tmp = strcmp( x, v );
        if ( tmp == 0 ) return -1;
        return tmp < 0 ? 0 : 1;
    }
};

void insert( Node * & o, char * x )
{
    if ( o == NULL )
    {
        o = new Node ();
        o->ch[0] = o->ch[1] = NULL;
        o->cnt = 1;
        strcpy( o->v, x );
        return ;
    }
    int d = o->cmp(x);
    if ( d == -1 ) 
    {
        o->cnt++;
        return ;
    }
    insert( o->ch[d], x );
}

void free( Node * o )
{
    if ( o != NULL )
    {
        free(o->ch[0]);
        free(o->ch[1]);
        delete o;
    }
}

void inorder( Node * o )
{
    if ( o )
    {
        inorder(o->ch[0]);
        printf("%s %.4f
", o->v, 100.0 * o->cnt / tot);
        inorder(o->ch[1]);
    }
}

Node * root;
char str[N];

int main ()
{
    root = NULL;
    tot = 0;
    while ( gets(str) != NULL )
    {
        tot++;
        insert( root, str );
    }
    inorder(root);
    free(root);
    return 0;
}