kmp模板

#include <iostream>
#include <cstdio>
#include <cstring>
#include <set>

using namespace std;

void getf(char* P, int* f)  
{  
	int m = strlen(P);  
    f[0] = 0;  
    f[1] = 0;  
    for(int i = 1; i < m; i++) {
    	
        int j = f[i];  
        while(j && P[i] != P[j]) {  
                j = f[j];  
        }  
        
        f[i + 1] = P[i] == P[j] ? j+1 : 0;  
        
    }  
}  
      
int kmp(char* T, char*P, int pos) {
  
    int n = strlen(T);
	int m = strlen(P);  
	int f[100005];
	
    getf(P, f);  
    int j = 0;  
    for(int i = pos; i < n; i++)  
    {  
        while(j && P[j] != T[i]) {  
            j = f[j];  
        }  
        if(P[j] == T[i]) {  
            j++;  
        }  
        if(j == m) {  
            return i - m + 1;  
        }  
    }  
    return -1;  
}  
int main() {
	
	char a[] = "abcdefghijk";
	char b[] = "defgh";
	
	int pos = kmp(a, b, 0);
	cout << pos << endl;
	
	return 0;
}