【POJ】2418 Hardwood Species

简单字典树。

#include <cstdio>
#include <cstring>
#include <cstdlib>

#define MAXN 128

typedef struct Trie {
    int count;
    Trie *next[MAXN];
    Trie() {
        count = 0;
        for (int i=0; i<MAXN; ++i)
            next[i] = NULL;
    }
} Trie;

Trie root;
char buf[35];
double n = 0;

void create(char str[]) {
    int i = 0, id;
    Trie *p = &root, *q;

    while (str[i]) {
        id = str[i];
        ++i;
        if (p->next[id] == NULL) {
            q = new Trie();
            p->next[id] = q;
        }
        p = p->next[id];
    }
    p->count++;
}

void dfs(Trie *t, int d) {
    int i;

    if (t->count) {
        buf[d] = '';
        printf("%s %.4lf
", buf, t->count*100.0/n);
    }
    for (i=0; i<MAXN; ++i) {
        if (t->next[i]) {
            buf[d] = i;
            dfs(t->next[i], d+1);
        }
    }
}

int main() {
    while (gets(buf) != NULL) {
        create(buf);
        n += 1.0;
    }
    dfs(&root, 0);
    return 0;
}