HDU_1711 Number Sequence（KMP）

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#define MAX_N 1000010
#define MAX_M 10010

using namespace std;

int T;
int result;
int A[MAX_N];
int B[MAX_M];
int len1,len2;
int Next[MAX_M];
void getnext();
int main()
{
scanf("%d",&T);
while( T-- ){
scanf("%d%d",&len1,&len2);
for( int i = 0; i < len1; i++ ){
scanf("%d",&A[i]);
}
for( int i = 0; i < len2; i++ ){
scanf("%d",&B[i]);
}
getnext();
result = -1;
for( int i = 0,j = 0; i < len1; i++ ){
while( j > 0 && A[i] != B[j] ){
j = Next[j];
}
if( A[i] == B[j] ){
j++;
}
if( j == len2 ){
result = i-len2+2;
break;
}
}
printf("%d\n",result);
}
return 0;
}

void getnext(){
Next[0] = -1;
Next[1] = 0;
int i = 0;
int j = -1;
while( i < len2 ){
if( j == -1 || B[i] == B[j] ){
Next[++i] = ++j;
}
else{
j = Next[j];
}
}
return ;
}