Longest increasing subsequence

#include<bits/stdc++.h>
using namespace std;
pair<int,int> lis(vector<int>&v,vector<int>&l){
    int n=v.size();
    if(n==0)
        return {0,-1};
    vector<int>dp(n,1);
    dp[0]=1;
    int s=1;
    int e=0;
    for(int i=1;i<n;i++){
        for(int j=0;j<i;j++){
            if(v[j]<v[i]&&dp[j]+1>dp[i]){
                dp[i]=dp[j]+1;
                l[i]=j;
            }
        }
        if(s<dp[i]){
            s=dp[i];
            e=i;
        }
    }
    return {s,e};
}
void print(vector<int>&v,vector<int>&p,int e){
    while(e>=0){
        cout<<v[e]<<" ";
        e=p[e];
    }
}

int main(){
    int n;
    cin>>n;
    vector<int>v;
    for(int i=0;i<n;i++){
        int c;
        cin>>c;
        v.push_back(c);
    }
    vector<int>l(n,-1);
    int s=lis(v,l).first;
    int e=lis(v,l).second;
    cout<<s<<endl;
    print(v,l,e);
    return 0;
}