所有点的错误信息均为 Two same edges appear.但我觉得自己的代码应该不会输出两条相同的边，求 hack

#include <bits/stdc++.h>
#define int long long
using namespace std;
void read(int &a)
{
	int s=0,w=1;
	char ch=getchar();
	while(ch<'0'||ch>'9'){
		if(ch=='-')w=-1;
		ch=getchar();
	}
	while(ch>='0'&&ch<='9'){
		s=s*10+ch-'0';
		ch=getchar();
	}
	a=s*w;
}
void write(int x)
{
    if(x<0)
        putchar('-'),x=-x;
    if(x>9)
        write(x/10);
    putchar(x%10+'0');
    return;
}
const int N=1e6+10;
int n,m,jl,ans1[N],ans2[N],t,jsq,jl1[N],jl2[N],tt;
struct node{
	int w,id;
}a[N];
bool cmp(node a,node b){
	return a.w<b.w;
}
int check(int x){
	int jsq=0;
	for(int i=2;i<n;i++){
		if(i>=jl){
			int l=i+1,r=n,jjl=i;
			while(l<=r){
				int mid=l+r>>1;
				if(a[i].w*a[mid].w<=x){
					jjl=mid;
					l=mid+1;
				}
				else r=mid-1;
			}
			jsq+=jjl-i;
		}
		else{
			int l=i+1,r=n-1,jjl=n;
			while(l<=r){
				int mid=l+r>>1;
				if(a[i].w*a[mid].w<=x){
					jjl=mid;
					r=mid-1;
				}
				else l=mid+1;
			}
			jsq+=n-jjl;
		}
	}
	int l=2,r=jl-1,jjl=jl;
	while(l<=r){
		int mid=l+r>>1;
		if(a[1].w*a[mid].w<=x){
			jjl=mid;
			r=mid-1;
		}
		else l=mid+1;
	}
	jsq+=jl-jjl;
	return (m<=jsq);
}
void print(){
	printf("%lld\n",jsq);
	for(int i=1;i<=t;i++){
		write(ans1[i]);
		putchar(' ');
		write(ans2[i]);
		puts("");
	}
	return;
}
signed main(){
	read(n),read(m);
	if(n==1){
		cout<<0;
		return 0;
	}
	m-=(n-1);
	for(int i=1;i<=n;i++){
		read(a[i].w);
		a[i].id=i;
	}
	sort(a+1,a+1+n,cmp);
	for(int i=1;i<=n;i++){
		if(a[i].w>=0){
			jl=i;
			break;
		}
	}
	int l=-1e12,r=1e12,ans=1e12;
	if(m!=0){
		while(l<=r){
			int mid=l+r>>1;
			if(check(mid)){
				r=mid-1;
				ans=mid;
			}
			else l=mid+1;
		}
	}
	for(int i=2;i<n;i++){
		if(a[i].w<0){
			jsq+=a[i].w*a[n].w;
		}
		else{
			jsq+=a[1].w*a[i].w;
		}
	}
	jsq+=a[1].w*a[n].w;
	t=n-1;
	ans1[1]=a[1].id,ans2[1]=a[n].id;
	for(int i=2;i<n;i++){
		if(a[i].w<0){
			ans1[i]=a[i].id,ans2[i]=a[n].id;
		}
		else{
			ans1[i]=a[1].id,ans2[i]=a[i].id;
		}
	}
	m+=(n-1);
	if(t==m){
		print();
		return 0;
	}
	for(int i=2;i<n;i++){
		if(i>=jl){
			int l=i+1,r=n,jjl=i;
			while(l<=r){
				int mid=l+r>>1;
				if(a[i].w*a[mid].w<=ans){
					jjl=mid;
					l=mid+1;
				}
				else r=mid-1;
			}
			for(int j=i+1;j<=jjl;j++){
				if(a[i].w*a[j].w==ans){
					jl1[++tt]=a[i].id,jl2[tt]=a[j].id;
				}
				else{
					ans1[++t]=a[i].id,ans2[t]=a[j].id;
					jsq+=a[i].w*a[j].w;
				}
				if(t==m){
					print();
					return 0;
				}
			}
		}
		else{
			int l=i+1,r=n-1,jjl=n;
			while(l<=r){
				int mid=l+r>>1;
				if(a[i].w*a[mid].w<=ans){
					jjl=mid;
					r=mid-1;
				}
				else l=mid+1;
			}
			for(int j=jjl;j<n;j++){
				if(a[i].w*a[j].w==ans){
					jl1[++tt]=a[i].id,jl2[tt]=a[j].id;
				}
				else{
					ans1[++t]=a[i].id,ans2[t]=a[j].id;
					jsq+=a[i].w*a[j].w;
				}
				if(t==m){
					print();
					return 0;
				}
			}
		}
	}
	l=2,r=jl;
	int jjl=jl;
	while(l<=r){
		int mid=l+r>>1;
		if(a[1].w*a[mid].w<=ans){
			jjl=mid;
			r=mid-1;
		}
		else l=mid+1;
	}
	for(int i=jjl;i<jl;i++){
		if(a[1].w*a[i].w==ans){
			jl1[++tt]=a[1].id,jl2[tt]=a[i].id;
		}
		else{
			ans1[++t]=a[1].id,ans2[t]=a[i].id;
			jsq+=a[1].w*a[i].w;
		}
		if(t==m){
			print();
			return 0;
		}
	}
	m-=t;
	jsq+=m*ans;
	printf("%lld\n",jsq);
	for(int i=1;i<=t;i++){
		write(ans1[i]);
		putchar(' ');
		write(ans2[i]);
		puts("");
	}
	for(int i=1;i<=m;i++){
		write(jl1[i]);
		putchar(' ');
		write(jl2[i]);
		puts("");
	}
	return 0;
}