唐仁 D球条

#include<bits/stdc++.h>
using namespace std;
unordered_map<int,int> u[12];
int a[200005];
long long m10[15];
signed main(){
	int n,m;
	cin>>n>>m;
	m10[1]=10%m;
	for(int i=2;i<=10;i++)
		m10[i]=(m10[i-1]*10)%m;
	for(int i=1;i<=n;i++){
		cin>>a[i];
		for(int j=1;j<=10;j++){
			u[j][(a[i]%m)*m10[j]%m]++;
		}
	}
	int k=0;
	for(int i=1;i<=n;i++){
		k+=u[int(log10(a[i]))+1][(m-a[i]%m)%m];
	}
	cout<<k;
	return 0;
}