F. We Were Both Children(埃氏筛思想)
作者:
travel2.0
,
2024-02-02 19:41:54
,
所有人可见
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阅读 59
埃氏筛思想(求所有青蛙的最多的公倍数)
void solve(int n){ // 时间复杂度降到 O(nlogn);
for(int i = 1;i<=n;i++){
for(int j = i;j<=n;j+=i) {
c[j] +=b[i];
}
}
for(int i = 1;i <= n;i++){
res = max(res,c[i]);
}
}
#include<bits/stdc++.h>
using namespace std;
int t;
#define pb push_back
const int N = 2e5 + 10;
int a[N],b[N],c[N];
int res = 0;
void solve(int n){
for(int i = 1;i<=n;i++){
for(int j = i;j<=n;j+=i) {
c[j] +=b[i];
}
}
for(int i = 1;i <= n;i++){
res = max(res,c[i]);
}
}
int main(){
ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);
cin>>t;
int n;
while(t--){
memset(a,0,sizeof a);
memset(b,0,sizeof b);
memset(c,0,sizeof c);
cin>>n;
for(int i = 1;i <= n;i++){
cin>>a[i];
if(a[i]<=n) b[a[i]] ++;
}
//for(int i = 1;i <= n;i++) cout<<b[i]<<' ';
//cout<<endl<<endl;
res = 0;
solve(n);
cout<<res<<endl;
}
return 0;
}