先预处理出，，复杂度为。以上纯属best code上的题解，确实不看题解我不会#include<iostream>#include<cstring>#include<algorithm>#define maxn 100000+5using namespace std;int mapp[maxn],head[maxn];int n;int main(){cin.sync_with_stdio(false);int t,casee=1;cin>>t;while(t–){cin>>n;memset(mapp,0,sizeof(mapp));memset(head,0,sizeof(head));int maxx=-1;for(int i=0;i<n;i++){int x;cin>>x;mapp[x]++;maxx=max(maxx,x);}for(int i=2;i<=maxx;i++){for(int j=i;j<=maxx;j+=i){if(mapp[j]) head[i]+=mapp[j];}}cout<<"Case #"<<casee++<<": ";for(int i=maxx;i>=1;i–){if(head[i]>=2) {cout<<i<<endl;break;}}}return 0;}
一定要记得挺身而出，即便帮不了忙，安慰也是最大的支持.
