MLE求助

不知道是数据量太大数组占内存太大，还是因为nextInt方法花销太大，如果是nextInt，这已经不是第一次了，所以有没有哪位大佬帮帮忙，怎么能低耗快速读取键盘输入，感激不尽

import java.util.Scanner;

public class Main{

    private static int[][] arr;

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int n = in.nextInt();
        arr = new int[n][];
        for (int i = 0; i < n; i++) {
            arr[i] = new int[i + 1];
            for(int j = 0; j <= i; j++){
                arr[i][j] = in.nextInt();
            }
        }
        System.out.println(findMax(n));
    }
    private static int findMax(int row){
        if(row == 1) return arr[0][0];
        for(int i = 1; i < row; ++i){
            for(int j = 0; j < arr[i].length; ++j){
                if(j == 0){
                    arr[i][j] += arr[i - 1][j];
                }else if(j == arr[i].length - 1){
                    arr[i][j] += arr[i - 1][j - 1];
                }else {
                    arr[i][j] += Math.max(arr[i - 1][j], arr[i - 1][j - 1]);
                }
            }
        }
        int max = Integer.MIN_VALUE;
        for(int i = 0; i < arr[row - 1].length; ++i){
            if(arr[row - 1][i] > max) max = arr[row - 1][i];
        }
        return max;
    }
}