C++(clang++ 11.0.1) 解法, 执行用时: 192ms, 内存消耗: 424K, 提交时间: 2023-08-13 21:14:33

#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int N=1e5+5;
int n,x,f[32][32];
ll ans;
int main()
{
    scanf("%d%d",&n,&x);
    for(int i=1;i<=n;i++)
    {
        int u,k2=0,k5=0;
        scanf("%d",&u);
        while(u%2==0)k2++,u/=2;
        while(u%5==0)k5++,u/=5;
        for(int j=0;j<32;j++)
        for(int l=0;l<32;l++)
        if(k2+j>=x&&k5+l>=x)ans+=f[j][l];
        f[k2][k5]++;
    }
    printf("%lld\n",ans);
}

pypy3 解法, 执行用时: 393ms, 内存消耗: 30880K, 提交时间: 2023-08-13 20:19:39

def read_ints():
    return [int(x) for x in input().split(' ')]

n,x=read_ints()
a=read_ints()

res=0
f=[[0]*30 for _ in range(13)]
fs=[0]*13

for i in range(n):
    f2=f5=0
    while a[i]%2==0:
        a[i]//=2
        f2+=1
    while a[i]%5==0:
        a[i]//=5
        f5+=1

    for i in range(max(0,x-f5),13):
        if fs[i]==0:continue
        res+=sum(f[i][max(0,x-f2):])

    f[f5][f2]+=1
    fs[f5]+=1

print(res)

C++(g++ 7.5.0) 解法, 执行用时: 186ms, 内存消耗: 448K, 提交时间: 2023-08-13 19:21:45

#include<bits/stdc++.h>
#define ll long long
using namespace std;
int sum[35][35],n,k,x; ll ans;
int main(){
	std::ios::sync_with_stdio(false);
	cin>>n>>k;
	for(int i=1;i<=n;i++){
		cin>>x;
		int tot1=0,tot2=0;
		while(x%2==0)tot1++,x/=2;
		while(x%5==0)tot2++,x/=5;
		for(int a=0;a<=31;a++)
		for(int b=0;b<=31;b++)
		if(tot1+a>=k&&tot2+b>=k) 
		ans+=sum[a][b];
		sum[tot1][tot2]++;
	}
	cout<<ans;
	return 0;
}