public class Naive { public static int longestSlideDown(int[][] pyramid, int row, int col) { if (row >= pyramid.length || col < 0 || col >= pyramid[row].length) { return Integer.MIN_VALUE; } if (row == pyramid.length - 1) { return pyramid[row][col]; } return pyramid[row][col] + Math.max( longestSlideDown(pyramid, row + 1, col), longestSlideDown(pyramid, row + 1, col + 1)); } public static int longestSlideDown(int[][] pyramid) { return longestSlideDown(pyramid, 0, 0); } public static void main(String[] args) { System.out.print("Test #1: "); System.out.println(longestSlideDown(new int[][] { { 3 }, { 7, 4 }, { 2, 4, 6 }, { 8, 5, 9, 3 } }) == 23 ? "passed" : "failed"); System.out.print("Test #2: "); System.out.println(longestSlideDown(new int[][] { { 75 }, { 95, 64 }, { 17, 47, 82 }, { 18, 35, 87, 10 }, { 20, 4, 82, 47, 65 }, { 19, 1, 23, 75, 3, 34 }, { 88, 2, 77, 73, 7, 63, 67 }, { 99, 65, 4, 28, 6, 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, 4, 68, 89, 53, 67, 30, 73, 16, 69, 87, 40, 31 }, { 4, 62, 98, 27, 23, 9, 70, 98, 73, 93, 38, 53, 60, 4, 23 }, }) == 1074 ? "passed" : "failed"); } }