CF #364 (Div. 2)（ A. Cards 简单模拟）

#include<cstdio>
#include<algorithm>
#include<iostream>
#include<vector>
#include<queue>
#include<cstring>
#include<bits/stdc++.h>
#include<map>
#include<string>
using namespace std;
#define cl(a,b) memset(a,b,sizeof(a))
#define LL long long
#define pb push_back
#define gcd __gcd

#define For(i,j,k) for(int i=(j);i<k;i++)
#define lowbit(i) (i&(-i))
#define _(x) printf("%d\n",x)

const int maxn = 1e2+200;
const LL inf  = 1LL << 34;

int a[maxn],n;
bool vis[maxn];
int getpos(int x){
for(int i=1;i<=n;i++){
if(vis[i])continue;
if(a[i]==x){
vis[i]=1;return i;
}
}
return -1;
}
int main(){

scanf("%d",&n);
int sum=0;
for(int i=1;i<=n;i++){
scanf("%d",&a[i]);sum+=a[i];
}
int avg = sum/(n/2);

vis[1]=1;
printf("1 %d\n",getpos(avg-a[1]));

for(int i=1;i<n/2;i++){
int A=1;
for(int j=1;j<=n;j++)if(!vis[j]){
A=j;vis[j]=1;break;
}
printf("%d %d\n",A,getpos(avg-a[A]));
}

return 0;
}