字典树水题。
1 #include <cstdio> 2 #include <cstring> 3 #include <cstdlib> 4 5 typedef struct Trie { 6 bool v; 7 Trie *next[2]; 8 } Trie; 9 10 Trie *root; 11 12 bool create(char str[]) { 13 int i = 0, id; 14 bool ret = false; 15 Trie *p = root, *q; 16 17 while (str[i]) { 18 id = str[i] - '0'; 19 ++i; 20 if (p->next[id] == NULL) { 21 q = (Trie *)malloc(sizeof(Trie)); 22 q->v = false; 23 q->next[0] = q->next[1] = NULL; 24 p->next[id] = q; 25 ret = true; 26 } else { 27 if (p->next[id]->v) 28 return false; 29 } 30 p = p->next[id]; 31 } 32 p->v = true; 33 34 return ret; 35 } 36 37 void del(Trie *t) { 38 if (t == NULL) 39 return ; 40 del(t->next[0]); 41 del(t->next[1]); 42 free(t); 43 } 44 45 int main() { 46 int t = 0; 47 char buf[25]; 48 bool f = true; 49 root = (Trie *)malloc(sizeof(Trie)); 50 root->next[0] = root->next[1] = NULL; 51 while (scanf("%s", buf) != EOF) { 52 if (buf[0] == '9') { 53 ++t; 54 if (f) 55 printf("Set %d is immediately decodable ", t); 56 else 57 printf("Set %d is not immediately decodable ", t); 58 f = true; 59 del(root); 60 root = (Trie *)malloc(sizeof(Trie)); 61 root->next[0] = root->next[1] = NULL; 62 } else { 63 if (f) 64 f = create(buf); 65 } 66 } 67 68 return 0; 69 }