NOIp模拟2最大公约数

 1 #include 
 2 using namespace std;
 3 
 4 int n, k, t, a[500050], b[500050], c[500050], maxx, tot, sum[500050];
 5 
 6 int main() {
 7     maxx=-0x7fffffff;
 8     cin >> n >> k;
 9     for (int i=1;i<=n;++i) {
10         scanf("%d", &a[i]);
11         maxx=max(maxx, a[i]);
12         b[a[i]]++;
13     }
14     for (int i=maxx;i;--i) {
15         tot=0;
16         for (int j=i;j<=maxx;j+=i)
17             tot+=b[j];
18         if (tot>=k) {
19             cout < endl;
20             return 0;
21         }
22     }
23 }