hihocoder KMP算法

 1 #include <cstdio>  
 2 #include <cstring>  
 3 #include <algorithm>  
 4 #include <iostream>  
 5 #include <string>  
 6 using namespace std;  
 7 
 8 int f[10005];  
 9 
10 void getfill(string s)  
11 {  
12     memset(f, 0, sizeof(f));
13     for(int i = 1; i < s.size(); i++)  
14     {  
15         int j = f[i];  
16         while(j && s[i] != s[j])  
17             j = f[j];  
18         f[i+1] = (s[i] == s[j]) ? j+1 : 0;  
19     }  
20 }  
21 
22 int find(string a, string s)  
23 {  
24     int ans = 0;  
25     getfill(s);
26     int j = 0;  
27     for(int i = 0; i < a.size(); i++)  
28     {  
29         while(j && a[i] != s[j])  
30             j = f[j];  
31         if(a[i] == s[j])  
32             j ++;  
33         if(j == s.size())
34         {  
35             ans ++;  
36         }  
37     }  
38     return ans;  
39 } 
40 
41 int main()
42 {
43     int n;
44     cin >> n;
45     string a, b;
46     for(int i = 0; i < n; i++)
47     {
48         cin >> a >> b;
49         cout << find(b, a) << endl;
50     }
51     return 0;
52 }