int n;cin >> n;
    vector<int> a(n);
    for(auto &x:a) cin >> x;
    a.insert(a.begin(),0);
    vector<vector<int>> dp(n+1,vector<int> (n+1,0));
    int ans=0;
    for(int i=1;i<=n;i++) {
        // last was chosen for Q
        for(int j=0;j<i-1;j++) {
            // choose this for P
            dp[i][i-1]=max(dp[i][i-1],dp[j][i-1]+(j>0?abs(a[i]-a[j]):0));
            ans=max(ans,dp[i][i-1]);
            // choose this for Q
            dp[j][i]=max(dp[j][i],dp[j][i-1]+(i-1>0?abs(a[i]-a[i-1]):0));
            ans=max(ans,dp[j][i]);
        }
        // last was chosen for P
        for(int j=0;j<i-1;j++) {
            // choose this for P
            dp[i][j]=max(dp[i][j],dp[i-1][j]+(i-1>0?abs(a[i]-a[i-1]):0));
            ans=max(ans,dp[i][j]);
            // choose this for Q
            dp[i-1][i]=max(dp[i-1][i],dp[i-1][j]+(j>0?abs(a[i]-a[j]):0));
            ans=max(ans,dp[i-1][i]);
        }
    }
    cout << ans << "\n";

AC Submission