codeforces 701A A. Cards(水题)

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <bits/stdc++.h>
#include <stack>

using namespace std;

#define For(i,j,n) for(int i=j;i<=n;i++)
#define mst(ss,b) memset(ss,b,sizeof(ss));

typedef  long long LL;

template<class T> void read(T&num) {
char CH; bool F=false;
for(CH=getchar();CH<'0'||CH>'9';F= CH=='-',CH=getchar());
for(num=0;CH>='0'&&CH<='9';num=num*10+CH-'0',CH=getchar());
F && (num=-num);
}
int stk[70], tp;
template<class T> inline void print(T p) {
if(!p) { puts("0"); return; }
while(p) stk[++ tp] = p%10, p/=10;
while(tp) putchar(stk[tp--] + '0');
putchar('\n');
}

const LL mod=1e9+7;
const double PI=acos(-1.0);
const int inf=1e9;
const int N=1e5+10;
const int maxn=500+10;
const double eps=1e-6;

int n,a[200],vis[200];

int main()
{
int n;
read(n);
int sum=0;
For(i,1,n)read(a[i]),sum+=a[i];
int le=2*sum/n;
For(i,1,n)
{
if(vis[i])continue;
For(j,1,n)
{
if(!vis[j]&&a[i]+a[j]==le&&i!=j)
{
cout<<i<<" "<<j<<endl;
vis[i]=1;
vis[j]=1;
break;
}
}
}
return 0;
}