Spell checker--POJ 1035
1、题目类型：字符串、暴力法、trie树。
2、解题思路：（1）记录字符串字典；（2）每输入一个字符串，查找字典中是否存在；（3）如果不存在，依次寻找其是否可以通过字典中字符串替换、添加、删除单个字符获得。
3、注意事项：string.h库函数的使用：trie树的指针的判断，TNode结构体的设计。
4、实现方法：（暴力法）
1 #include <iostream>
2 #include <string>
3 #include <vector>
4 using namespace std;
5
6 int ok;
7 int ldic, lstr;
8 string current;
9
10 vector<string> dic;
11
12 void Init()
13 {
14 /* 读数据 */
15 while(1)
16 {
17 cin >> current;
18 if (current == "#") break;
19 dic.push_back(current);
20 }
21
22 }
23 /* 替换一个字符 */
24 void replace(string dic)
25 {
26 int count = 0;
27 /* 只有一个字符不一样就OK */
28 for (int i = 0; i < dic.length(); i++)
29 {
30 if (current[i] != dic[i]) count++;
31 if (count > 1) return;
32 }
33 ok = 1;
34 cout << " " + dic;
35 }
36
37 /* 增加一个字符 */
38 void insert(string dic)
39 {
40 string tmp;
41 for (int i = 0; i < current.length(); i++)
42 {
43 /* 在不同位置增加字符 */
44 if (current[i] != dic[i])
45 {
46 tmp = dic;
47 tmp.insert(i, 1, current[i]);
48 if (tmp == current)
49 {
50 ok = 1;
51 cout << " " + dic;
52 }
53 return;
54 }
55 }
56 }
57
58 /* 删除一个字符 */
59 void del(string dic)
60 {
61 string tmp;
62 for (int i = 0; i < dic.length(); i++)
63 {
64 /* 删除不同位置的字符 */
65 if (current[i] != dic[i])
66 {
67 tmp = dic;
68 tmp.erase(i, 1);
69 if (tmp == current)
70 {
71 ok = 1;
72 cout << " " + dic;
73 }
74 return;
75 }
76 }
77 }
78
79 void Seach()
80 {
81 ok = -1;
82 lstr = current.length();
83 /* 判断是否correct */
84 for (int i = 0; i < dic.size(); i++)
85 {
86 if (dic[i] == current)
87 {
88 cout << current + " is correct";
89 ok = 0;
90 break;
91 }
92 }
93 /* 处理 */
94 if (ok < 0)
95 {
96 cout << current + ':';
97 for (int i = 0; i < dic.size(); i++)
98 {
99 ldic = dic[i].length();
100 if (lstr == ldic)
101 {
102 replace(dic[i]);
103 }
104 else if (lstr == ldic + 1)
105 {
106 insert(dic[i]);
107 }
108 else if (lstr == ldic - 1)
109 {
110 del(dic[i]);
111 }
112 }
113 }
114 }
115 int main()
116 {
117 Init();
118 while(1)
119 {
120 cin >> current;
121 if (current == "#") break;
122 Seach();
123 cout << endl;
124 }
125 return 0;
126 }
5、实现方法：（trie树）
1 #include <iostream>
2 using namespace std;
3
4 char word[10001][27],res[10001][27];
5 int n,m,len,cnt;
6 bool flag;
7
8 struct TNode
9 {
10 int index,len;
11 TNode *p[26];
12 TNode()
13 {
14 index = -1;
15 len = 0;
16 for(int i = 0 ; i < 26; i++)
17 p[i] = NULL;
18 }
19 }root;
20
21 void Create(char *str)
22 {
23 int len1 = strlen(str);
24 TNode *ptr = &root;
25 for(int i = 0 ; i < len1; i++)
26 {
27 if(ptr->p[str[i]-'a'] == NULL)
28 ptr->p[str[i]-'a'] = new TNode();
29 ptr = ptr->p[str[i]-'a'];
30 }
31 ptr->index = cnt++;
32 ptr->len = len1;
33 }
34
35 int search(char *str)
36 {
37 int len1 = strlen(str);
38 TNode *ptr = &root;
39 for(int i = 0 ; i < len1; i++)
40 {
41 if(ptr->p[str[i]-'a'] == NULL)
42 return -1;
43 ptr = ptr->p[str[i]-'a'];
44 }
45 if(ptr->len == len1)
46 return ptr->index;
47 else return -1;
48 }
49
50 void ADD(char *str)
51 {
52 int pos,len1=strlen(str),i,k;
53 char z,temp[30];
54 for(i=0;i<=len1;i++)
55 {
56 for(z='a';z<='z';z++)
57 {
58 for(k=0;k<i;k++)
59 temp[k]=str[k];
60 temp[i]=z;
61 for(k=i+1;k<=len1;k++)
62 temp[k]=str[k-1];
63 temp[len1+1]='\0';
64 pos=search(temp);
65 if(pos == -1)
66 continue;
67 strcpy(res[pos],temp);
68 flag = 1;
69 }
70 }
71 }
72 void Delete(char *str)
73 {
74 char temp[30];
75 int pos,i,j,k,len1=strlen(str);
76 for(i=0;i<len1;i++)
77 {
78 k=0;
79 for(j=0;j<len1;j++)
80 {
81 if(j==i)
82 continue;
83 temp[k++]=str[j];
84 }
85 temp[k]='\0';
86 pos=search(temp);
87 if(pos == -1)
88 continue;
89 strcpy(res[pos],temp);
90 flag = 1;
91 }
92 }
93 void Change(char *str)
94 {
95 int len1=strlen(str),i,j,pos;
96 char z, temp[30];
97 for(j=0;j<len1;j++)
98 temp[j]=str[j];
99 temp[len1]='\0';
100 for(i=0;i<len1;i++)
101 {
102 for(z='a';z<='z';z++)
103 {
104 if(z==str[i])
105 continue;
106 temp[i]=z;
107 pos=search(temp);
108 if(pos == -1)
109 continue;
110 strcpy(res[pos],temp);
111 flag = 1;
112 }
113 temp[i] = str[i];
114 }
115 }
116
117 int main()
118 {
119 int i;
120 for(i = 0 ; ; i++)
121 {
122 scanf("%s",word[i]);
123 if(word[i][0] == '#')
124 break;
125 Create(word[i]);
126 }
127 n = i;
128 char query[30];
129 for(i = 0 ; ; i++)
130 {
131 flag = false;
132 scanf("%s",query);
133 memset(res,0,sizeof(res));
134 if(query[0] == '#')
135 break;
136 int kk = search(query);
137 if(kk != -1)
138 {
139 cout<<query<<" is correct"<<endl;
140 continue;
141 }
142 ADD(query);
143 Delete(query);
144 Change(query);
145 if(flag)
146 {
147 cout<<query<<":";
148 for(int k = 0 ; k < 10001 ;k++)
149 if(res[k][0] != 0)
150 cout<<" "<<res[k];
151 cout<<endl;
152 }
153 else
154 cout<<query<<":"<<endl;
155 }
156 return 0;
157 }
