KMP模板

//主串a, 模式串b
char a[maxn], b[maxn];
int nxt[maxn];
int la, lb;

void getNext(){
	int j = 0;
	rep(i, 2, lb){
		while(j && b[i] != b[j+1]) j = nxt[j];    
		if(b[j+1] == b[i])j++;    
		nxt[i] = j;
	}
}

void kmp(){
	int j = 0;
	rep(i, 1, la){
		while(j > 0 && b[j+1] != a[i]) j = nxt[j];
		if(b[j+1] == a[i]) j++;
		if(j == lb) j = nxt[j];
	}
}

//la = strlen(a + 1), lb = strlen(b + 1);