Project Euler NO18

從下面的三角形的頂端開始，向下面一行的相鄰數字移動，從頂端到底端的最大總和爲23.

3
7 4
2 4 6
8 5 9 3

也就是 3 + 7 + 4 + 9 = 23.

找出從以下三角形的頂端走到底端的最大總和：

75
95 64
17 47 82
18 35 87 10
20 04 82 47 65
19 01 23 75 03 34
88 02 77 73 07 63 67
99 65 04 28 06 16 70 92
41 41 26 56 83 40 80 70 33
41 48 72 33 47 32 37 16 94 29
53 71 44 65 25 43 91 52 97 51 14
70 11 33 28 77 73 17 78 39 68 17 57
91 71 52 38 17 14 91 43 58 50 27 29 48
63 66 04 68 89 53 67 30 73 16 69 87 40 31
04 62 98 27 23 09 70 98 73 93 38 53 60 04 23

import java.util.Scanner;

public class Problem18
{
	public static void main(String[] args)
	{
		int array[][] = new int [15][15];
		Scanner sc = new Scanner(System.in);
		
		for (int i = 0; i < 15; i++)
		{
			String str = sc.nextLine();
			String sp[] = str.split("\\s+");
			for (int j = 0; j <= i; j++)
			{
				array[i][j] = Integer.parseInt(sp[j]);
			}
		}
		
		long start = System.currentTimeMillis();
		System.out.print("answer:  ");
		
		howmany(array, 0, 0, 0);
		System.out.println(max);
		
		long end = System.currentTimeMillis();
		System.out.print("time:  ");
		System.out.println(end - start);
	}
	
	static int max = 0;
	static void howmany(int array[][], int i, int j, int sum)
	{
		if (i == 15)
		{
			if (max < sum)
			{
				max = sum;
			}
			return;
		}
		
		howmany(array, i + 1, j, sum + array[i][j]);
		
		howmany(array, i + 1, j + 1, sum+ array[i][j]);
		
	}
}

answer:  1074
time:  8