HDU 1686 (KMP模式串出现的次数) Oulipo

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 
 5 using namespace std;
 6 
 7 const int maxn1 = 10000 + 10;
 8 const int maxn2 = 1000000 + 10;
 9 char W[maxn1], T[maxn2];
10 int next[maxn1];
11 
12 void get_next(char* W, int l)
13 {
14     int k = -1, j = 0;
15     next[0] = -1;
16     while(j < l)
17     {
18         if(k == -1 || W[k] == W[j])
19         {
20             ++k;
21             ++j;
22             next[j] = k;
23         }
24         else k = next[k];
25     }
26 }
27 
28 int KMP(char* W, int lenw, char* T, int lent)
29 {
30     int i = 0, j = 0, ans = 0;
31     while(i < lent)
32     {
33         if(j == -1 || T[i] == W[j])
34         {
35             ++i;
36             ++j;
37         }
38         else j = next[j];
39         if(j == lenw)
40         {
41             ans++;
42             j = next[j];
43         }
44     }
45     return ans;
46 }
47 
48 int main()
49 {
50     //freopen("in.txt", "r", stdin);
51     int kase;
52     scanf("%d", &kase);
53     while(kase--)
54     {
55         memset(next, 0, sizeof(next));
56         scanf("%s%s", W, T);
57         int lenw = strlen(W);
58         int lent = strlen(T);
59         get_next(W, lenw);
60         printf("%d\n", KMP(W, lenw, T, lent));
61     }
62 
63     return 0;
64 }