C++ :

#include <bits/stdc++.h>
using namespace std;

int main(){ 
	int a[1000]={0},n,i,r[1000]={0},k,p,j,x[1000][100]={0};
	cin>>n;
	for(i=1;i<=n;i++){
		cin>>a[i];
	}
	
	k=0; 
	for(i=1;i<=n;i++){ 
		p=-1; 
		for(j=1;j<=k;j++){
			if(r[j]>=a[i]){
				if(p==-1){
					p = j;
				} else if(r[j]<r[p]){
					p=j;
				}
			} 
		}  
		if(p==-1){
			k++;
			r[k]=a[i];
			x[k][1]=a[i];
		}else{
			r[p]=a[i];
			for(int yy=1;yy<=n;yy++){
				if(x[p][yy]==0){
					x[p][yy]=a[i];
					break;
				}
			}
		}
	} 
	
	cout<<k<<endl;
	for(int i=1;i<=k;i++){
		cout<<i<<":";
		for(int j=1;x[i][j]!=0;j++){
			cout<<x[i][j]<<" ";
		}
		cout<<endl;
	}
}

Python :

n=int(input())
sr=input().split()
a=[0 for i in range(n)]
for i in range(n):
    a[i]=int(sr[i])
k=0
k1=[0]
k1[0]=a[0]
k2=["1:"]
k2[0]=k2[0]+str(a[0])
for i in range(1,n):
    f=1
    for j in range(k+1):
        if(a[i]<k1[j]):
            f=0
            break
    if(f==1):
        k=k+1
        k1.append(a[i])
        k2.append(str(k+1)+":"+str(a[i]))
    else:
        k1[j]=a[i]
        k2[j]=k2[j]+" "+str(a[i])
print(k+1)
for i in range(k+1):
    print(k2[i])