站外题求条，玄一关，最长不降子序列

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define ft first
#define sd second
#define fs(i,x,y) for(int i=(x);i<=(y);i++)
#define fj(i,x,y) for(int i=(x);i>=(y);i--)
int p[5010]={0};
signed main(){
	std::ios::sync_with_stdio(false);
	cin.tie(0); 
	cout.tie(0);
    int n,a[5010]={0},dp[5010]={0};
    cin>>n;
    for(int i=1;i<=n;i++)cin>>a[i];
    fj(i,n,1){
        int maxx=0;
        fs(j,i+1,n)if(a[j]>=a[i]&&dp[j]>maxx)maxx=dp[j],p[i]=j;
        dp[i]=maxx+1;
    }
    int maxx=0;
    fs(i,1,n)maxx=max(maxx,dp[i]);
    cout<<"max="<<maxx<<'\n';
    fs(i,1,n)
    if(maxx==dp[i]){
        int x=i;
        while(x){
            cout<<a[x]<<' ';
            x=p[x];
        }
    }
	return 0;
}