【POJ】1035 Spell checker

字典树。
  1 #include <iostream>
  2 #include <cstdio>
  3 #include <cstring>
  4 #include <cstdlib>
  5 #include <vector>
  6 #include <string>
  7 using namespace std;
  8 
  9 typedef struct Trie {
 10     int in;
 11     Trie *next[26];
 12 } Trie;
 13 
 14 Trie root;
 15 char map[10005][25];
 16 int nums[205], nn;
 17 
 18 void create(char str[], int in) {
 19     int i = 0, j, id;
 20     Trie *p = &root, *q;
 21 
 22     while (str[i]) {
 23         id = str[i] - 'a';
 24         ++i;
 25         if (p->next[id] == NULL) {
 26             q = (Trie *)malloc(sizeof(Trie));
 27             q->in = -1;
 28             for (j=0; j<26; ++j)
 29                 q->next[j] = NULL;
 30             p->next[id] = q;
 31         }
 32         p = p->next[id];
 33     }
 34     p->in = in;
 35 }
 36 
 37 int find(char str[], int x) {
 38     int i = 0, id;
 39     Trie *p = &root;
 40 
 41     while (str[i]) {
 42         if (i == x) {
 43             ++i;
 44             continue;
 45         }
 46         id = str[i] - 'a';
 47         ++i;
 48         if (p->next[id] == NULL)
 49             return -1;
 50         p = p->next[id];
 51     }
 52 
 53     return p->in;
 54 }
 55 
 56 void ffind(char str[]) {
 57     int len = strlen(str), i, j, k;
 58     char ch, bk, bf[25];
 59     nn = 0;
 60 
 61     for (i=0; i<=len; ++i)
 62         bf[i] = str[i];
 63     for (i=0; i<len; ++i) {
 64         bk = bf[i];
 65         for (ch='a'; ch<='z'; ++ch) {
 66             if (ch == bk)
 67                 continue;
 68             bf[i] = ch;
 69             j = find(bf, -1);
 70             if (j != -1)
 71                 nums[nn++] = j;
 72         }
 73         bf[i] = bk;
 74     }
 75 
 76     for (i=0; i<len; ++i) {
 77         j = find(bf, i);
 78         if (j != -1)
 79             nums[nn++] = j;
 80     }
 81     bf[len+1] = '';
 82     for (i=0; i<=len; ++i) {
 83         k = j = 0;
 84         while (j<len) {
 85             if (k != i) {
 86                 bf[k] = str[j];
 87                 ++j;
 88             }
 89             ++k;
 90         }
 91         for (ch='a'; ch<='z'; ++ch) {
 92             bf[i] = ch;
 93             j = find(bf, -1);
 94             if (j != -1)
 95                 nums[nn++] = j;
 96         }
 97     }
 98 }
 99 
100 int comp(const void *a, const void *b) {
101     return *(int *)a - *(int *)b;
102 }
103 
104 int main() {
105     int n = 0, f;
106     char buf[25];
107 
108     for (int i=0; i<26; ++i)
109         root.next[i] = NULL;
110 
111     while (scanf("%s", map[n])!=EOF && map[n][0]!='#') {
112         create(map[n], n);
113         ++n;
114     }
115 
116     while (scanf("%s", buf)!=EOF && buf[0]!='#') {
117         f = find(buf, -1);
118         if (f != -1) {
119             printf("%s is correct
", buf);
120             continue;
121         }
122         ffind(buf);
123         printf("%s:", buf);
124         if (nn) {
125             qsort(nums, nn, sizeof(int), comp);
126             for (int i = 0; i<nn; ++i) {
127                 if (i && nums[i] == nums[i-1])
128                     continue;
129                 printf(" %s", map[nums[i]]);
130             }
131         }
132         printf("
");
133     }
134 
135     return 0;
136 }