C++ :

#include<iostream>
#include<queue>
using namespace std;
const int N=2e5+10;
#define int long long
inline int fread(){
	char ch=getchar();
	int n=0,m=1;
	while(ch<'0' or ch>'9'){
		if(ch=='-'){
			m=-1;
		}
		ch=getchar();
	}
	while(ch>='0' and ch<='9'){
		n=(n<<3)+(n<<1)+ch-48;
		ch=getchar();
	}
	return n*m;
}
int n,sum,a[N];
bool flag[N];
struct node{
	int m,x,y;
}z,p,q;
queue<node>q1,q2;
signed main(){
	n=fread();
	for(int i=1;i<=n;i++){
		a[i]=fread();
	}
	a[n+1]=!a[n];
	for(int i=2,j=1;i<n+2;i++){
		if(a[i]!=a[i-1]){
			q1.push((node){j,i-1,a[i-1]});
			j=i;
		}
	}
	sum=n;
	while(sum){
		while(q1.size()){
			z=q1.front();
			q1.pop();
			while(flag[z.m] and z.m<=z.x){
				z.m++;
			}
			if(z.m>z.x){
				continue;
			}
			printf("%d ",z.m);
			sum--;
			flag[z.m]=true;
			if(z.x==z.m){
				continue;
			}
			z.m++;
			q2.push(z);
		}
		puts("");
		while(q2.size()){
			q=q2.front(),q2.pop();
			while(q2.size()){
				p=q2.front();
				if(p.y==q.y){
					q.x=p.x,q2.pop();
				}else{
					break;
				}
			}
			q1.push(q);
		}
	}
	return 0;
}