【POJ】2001 Shortest Prefixes

字典树。

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

 #define MAXN 26

 typedef struct Trie{
     int n;
     Trie *next[MAXN];
 } Trie;

 Trie root;
 char buf[][];

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

     for (i=; i<len; ++i) {
         id = str[i] - 'a';
         if (p->next[id] == NULL) {
             q = (Trie *)malloc(sizeof(Trie));
             q->n = ;
             for (j=; j<MAXN; ++j)
                 q->next[j] = NULL;
             p->next[id] = q;
             p = p->next[id];
         } else {
             p->next[id]->n++;
             p = p->next[id];
         }
     }
 }

 int find(char str[]) {
     int len = strlen(str), i, id;
     Trie *p = &root;

     for (i=; i<len; ++i) {
         id = str[i] - 'a';
         if (p->next[id] == NULL)
             return i;
         else {
             if (p->next[id]->n == )
                 return i;
             p = p->next[id];
         }
     }

     return len;
 }

 void del(Trie *t) {
     int i;

     if (t == NULL)
         return ;
     for (i=; i<MAXN; ++i)
         del(t->next[i]);

     free(t);
 }

 int main() {
     int n = ;
     int i = , j;

     for (i=; i<MAXN; ++i)
         root.next[i] = NULL;
     root.n = -;

     while (scanf("%s", buf[n]) != EOF) {
         create(buf[n]);
         ++n;
     }

     for (i=; i<n; ++i) {
         printf("%s ", buf[i]);
         j = find(buf[i]);
         buf[i][j+] = '\0';
         printf("%s\n", buf[i]);
     }

     return ;
 }