yukicoder No.209

yukicoder209.cpp

#include <iostream>
#include <iomanip>
#include <vector>
#include <algorithm>
#include <numeric>
#include <functional>
#include <cmath>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <sstream>
#include <string>
#define repd(i,a,b) for (int i=(int)(a);i<(int)(b);i++)
#define rep(i,n) repd(i,0,n)
#define all(x) (x).begin(),(x).end()
#define mod 1000000007
#define inf 2000000007
#define mp make_pair
#define pb push_back
typedef long long ll;
using namespace std;
template <typename T>
inline void output(T a, int p) {
    if(p) cout << fixed << setprecision(p)  << a << "\n";
    else cout << a << "\n";
}
// end of template

void calc(vector<int> &X, vector<vector<int>> &dp){
    repd(i, 1, X.size()){
        rep(j, i){
            if (X[i] > X[j]) {
                dp[i][j]++;
            }
            rep(k, j){
                if (X[j] > X[k] && X[j] - X[k] < X[i] - X[j]) {
                    dp[i][j] = max(dp[i][j], dp[j][k] + 1);
                }
            }
        }
    }
}

int main() {
    cin.tie(0);
    ios::sync_with_stdio(0);
    // source code
    int Q;
    cin >> Q;
    rep(q, Q){
        int N;
        cin >> N;
        vector<int> A(N);
        vector<vector<int>> dp(N, vector<int>(N, 1));
        rep(i, N){
            cin >> A[i];
        }
        vector<int> L(N, 0), R(N, 0);
        calc(A, dp);
        rep(i, N){
            rep(j, N){
                L[i] = max(L[i], dp[i][j]);
            }
        }
        reverse(all(A));
        dp.assign(N, vector<int>(N, 1));
        calc(A, dp);
        rep(i, N){
            rep(j, N){
                R[i] = max(R[i], dp[i][j]);
            }
        }
        int ret = 0;
        rep(i, N){
            ret = max(ret, L[i] + R[N - i - 1] - 1);
        }
        output(ret, 0);
        
    }
    return 0;
}