【POJ】1035 Spell checker

字典树。

 #include <iostream>
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>
 #include <vector>
 #include <string>
 using namespace std;

 typedef struct Trie {
     int in;
     Trie *next[];
 } Trie;

 Trie root;
 char map[][];
 int nums[], nn;

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

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

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

     while (str[i]) {
         if (i == x) {
             ++i;
             continue;
         }
         id = str[i] - 'a';
         ++i;
         if (p->next[id] == NULL)
             return -;
         p = p->next[id];
     }

     return p->in;
 }

 void ffind(char str[]) {
     int len = strlen(str), i, j, k;
     char ch, bk, bf[];
     nn = ;

     for (i=; i<=len; ++i)
         bf[i] = str[i];
     for (i=; i<len; ++i) {
         bk = bf[i];
         for (ch='a'; ch<='z'; ++ch) {
             if (ch == bk)
                 continue;
             bf[i] = ch;
             j = find(bf, -);
             if (j != -)
                 nums[nn++] = j;
         }
         bf[i] = bk;
     }

     for (i=; i<len; ++i) {
         j = find(bf, i);
         if (j != -)
             nums[nn++] = j;
     }
     bf[len+] = '\0';
     for (i=; i<=len; ++i) {
         k = j = ;
         while (j<len) {
             if (k != i) {
                 bf[k] = str[j];
                 ++j;
             }
             ++k;
         }
         for (ch='a'; ch<='z'; ++ch) {
             bf[i] = ch;
             j = find(bf, -);
             if (j != -)
                 nums[nn++] = j;
         }
     }
 }

 int comp(const void *a, const void *b) {
     return *(int *)a - *(int *)b;
 }

 int main() {
     int n = , f;
     char buf[];

     for (int i=; i<; ++i)
         root.next[i] = NULL;

     while (scanf("%s", map[n])!=EOF && map[n][]!='#') {
         create(map[n], n);
         ++n;
     }

     while (scanf("%s", buf)!=EOF && buf[]!='#') {
         f = find(buf, -);
         if (f != -) {
             printf("%s is correct\n", buf);
             continue;
         }
         ffind(buf);
         printf("%s:", buf);
         if (nn) {
             qsort(nums, nn, sizeof(int), comp);
             for (int i = ; i<nn; ++i) {
                 if (i && nums[i] == nums[i-])
                     continue;
                 printf(" %s", map[nums[i]]);
             }
         }
         printf("\n");
     }

     return ;
 }