虽然暴力，但为什么才拿40分

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#define L long long
using namespace std;
const int N=100005;
const L M=10007;
int n,m;
L ans,a[N],b[N];
int main(){
	scanf("%d%d",&n,&m);
	for(int i=1;i<=n;i++)scanf("%lld",&a[i]),a[i]%=M;
	for(int i=1;i<=n;i++)scanf("%lld",&b[i]);
	for(int i=1;i<=n;i++){
		for(int j=i+2;j<=n;j+=2){
			if(b[i]==b[j])ans+=(i*1ll+j*1ll)%M*(a[i]+a[j])%M;
		}
	}
	printf("%lld",ans);
	return 0;
}