https://codeforces.com/contest/1154/problem/G

题意：给定数组，求其中lcm(a,b)的最小的a和b的位置。

题解：枚举GCD

/*
*@Author:   STZG
*@Language: C++
*/
#include <bits/stdc++.h>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstring>
#include<cstdio>
#include<string>
#include<vector>
#include<bitset>
#include<queue>
#include<deque>
#include<stack>
#include<cmath>
#include<list>
#include<map>
#include<set>
//#define DEBUG
#define RI register int
#define endl "\n"
using namespace std;
typedef long long ll;
//typedef __int128 lll;
const int N=10000000+10;
const int M=100000+10;
const int MOD=1e9+7;
const double PI = acos(-1.0);
const double EXP = 1E-8;
const int INF = 0x3f3f3f3f;
int t,n,m,k,p,l,r,u,v;
ll ans[2],cnt,flag,temp,sum;
int vis[N];
char str;
int main()
{
#ifdef DEBUG
	freopen("input.in", "r", stdin);
	//freopen("output.out", "w", stdout);
#endif
    //ios::sync_with_stdio(false);
    //cin.tie(0);
    //cout.tie(0);
    //scanf("%d",&t);
    //while(t--){
    scanf("%d",&n);
    ll maxl=1e18;
    for(int i=1;i<=n;i++){
        scanf("%d",&m);
        if(vis[m]){
            ll tempmax=m;
            if(tempmax<maxl){
                maxl=tempmax;
                ans[0]=vis[m];
                ans[1]=i;
            }
        }
        vis[m]=i;
    }
    for(int i=1;i<N;i++){
        sum=0;
        temp=0;
        for(int j=i;j<N;j+=i){
            if(vis[j])
                sum++;
            else
                continue;
            if(sum&&!temp)
                temp=j;
            if(sum>=2){
                ll tempmax=temp/i*j;
                //cout<<temp<<j<<endl;
                if(tempmax<maxl){
                    maxl=tempmax;
                    ans[0]=vis[temp];
                    ans[1]=vis[j];
                }
                break;
            }
        }
    }
    if(ans[0]>ans[1])
        swap(ans[0],ans[1]);
    cout<<ans[0]<<" "<<ans[1]<<endl;
    //}

#ifdef DEBUG
	printf("Time cost : %lf s\n",(double)clock()/CLOCKS_PER_SEC);
#endif
    //cout << "Hello world!" << endl;
    return 0;
}