[](题目详情 - 求和 - Hydro) #include<bits/stdc++.h> using namespace std; long long n,m,num[100005],c[100005],sum[100005],ans=0; long long sum1[2][100007],sum2[2][100007],sum3[2][100007],sum4[2][100007]; int main(){ freopen("sum.in", "r", stdin); freopen("sum.out", "w", stdout); ios::sync_with_stdio(0); cin.tie(0), cout.tie(0); cin>>n>>m; for(int i=1;i<=n;i++) cin>>num[i]; for(int i=1;i<=n;i++) cin>>c[i]; for(int i=1;i<=n;i++){ ans+=sum1[i%2][c[i]]%10007; ans+=sum2[i%2][c[i]]*num[i]%10007; ans+=sum3[i%2][c[i]]i%10007; ans+=sum4[i%2][c[i]]i%10007num[i]%10007 ; sum1[i%2][c[i]]+=inum[i]%10007; sum2[i%2][c[i]]+=i%10007; sum3[i%2][c[i]]+=num[i]%10007; sum4[i%2][c[i]]+=1%10007; } cout<<ans%10007; return 0; }