KMP算法模板

 

 1 #include <cstdio>

 2 #include <cstring>

 3 using namespace std;

 4 #define N 10010

 5 #define M 1000010

 6 

 7 char S[M], T[N];

 8 int next[N];

 9 

10 void Get_next()

11 {

12     int i=0, j=-1;

13     next[0] = -1;

14     int lt = strlen(T);

15     while(i<lt)

16     {

17         if(j==-1 || T[i]==T[j])

18             next[++i] = ++j;

19         else j = next[j];

20     }

21 }

22 

23 int KMP()

24 {

25     int i=0, j=0, cnt=0;

26     int ls = strlen(S), lt=strlen(T);

27     Get_next();

28     while(i<ls && j<lt)

29     {

30         if(S[i]==T[j] || j==-1)

31             i++, j++;

32         else

33             j = next[j];

34         if(j==lt) //得到一个子串

35         {

36             cnt++;

37             j = next[j];

38         }

39     }

40     return cnt;

41 }

42 

43 int main()

44 {

45     int n;

46     while(~scanf("%d", &n))

47     {

48         for(int i=0; i<n; i++)

49         {

50             scanf("%s%s", T, S);

51             printf("%d\n", KMP());

52         }

53     }

54     return 0;

55 }