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
}