adding working solution - from bottom.

067/Bottom.java

@@ -0,0 +1,29 @@
+import java.util.Arrays;
+
+public class Bottom {
+	public static void main(String[] args) { 
+		System.out.println(fromBottom());
+	}
+
+	public static int fromBottom() { 
+		int[][] triangle = LoadTriangle.loadTriangle();
+		int[][] triangleSum = LoadTriangle.loadTriangle();
+		int dim = triangle.length;
+		int sum = 0;
+		// Rows go from second to last to first
+		for(int r=dim-2; r>=0; r--) { 
+			// Columns go from 0 to r
+			for(int j=0; j<=r; j++) {
+				// Find maximum path for this three-element subtree
+				int left = triangleSum[r+1][j];
+				int right = triangleSum[r+1][j+1];
+				if(left > right) { 
+					triangleSum[r][j] = triangleSum[r+1][j] + triangle[r][j];
+				} else {
+					triangleSum[r][j] = triangleSum[r+1][j+1] + triangle[r][j];
+				}
+			}
+		}
+		return triangleSum[0][0];
+	}
+}

067/BruteForce.java

@@ -1,25 +1,19 @@
 import java.util.Arrays;
-import java.util.Scanner;
-import java.io.FileReader;
-import java.io.BufferedReader;
-import java.io.FileNotFoundException;
 
 public class BruteForce {
 
-	public static final String FILE = "small.txt";
-
 	public static int max = 0;
 	public static String maxPath = "";
 
 
-	public static void main(String[] args) throws FileNotFoundException {
+	public static void main(String[] args) {
 		System.out.println(bruteForcePath());
 		System.out.println(maxPath);
 	}
 
 
-	public static int bruteForcePath() throws FileNotFoundException {
-		int[][] triangle = loadTriangle();
+	public static int bruteForcePath() {
+		int[][] triangle = LoadTriangle.loadTriangle();
 		int dim = triangle.length;
 
 		boolean[] goright = new boolean[dim];
@@ -81,37 +75,5 @@ public class BruteForce {
 		}
 		return sum;
 	}
-
-
-	/** Load a triangle from a file. */
-	public static int[][] loadTriangle() throws FileNotFoundException {
-		int nlines = countLines();
-		int[][] triangle = new int[nlines][nlines];	
-		Scanner s = new Scanner(new BufferedReader(new FileReader(FILE)));
-		int r = 0;
-		while(s.hasNextLine()) {
-			String line = s.nextLine();
-			Scanner ls = new Scanner(line);
-			int c = 0;
-			while(ls.hasNextInt()) {
-				int num = ls.nextInt();
-				triangle[r][c] = num;
-				c++;
-			}
-			r++;
-		}
-		return triangle;
-	}
-
-	/** Count the number of lines in the triangle file. */ 
-	public static int countLines() throws FileNotFoundException { 
-		Scanner s = new Scanner(new BufferedReader(new FileReader(FILE)));
-		int lines = 0;
-		while(s.hasNextLine()) { 
-			s.nextLine();
-			lines++;
-		}
-		return lines;
-	}
 }
 

067/Path.java

@@ -1,13 +1,7 @@
 import java.util.Arrays;
-import java.util.Scanner;
-import java.io.FileReader;
-import java.io.BufferedReader;
-import java.io.FileNotFoundException;
 
 public class Path {
 
-	public static final String FILE = "triangle_counterexample1.txt";
-
 	/** Find the maximum path down a triangle.
 	 *
 	 * Strategy: add up the marginal sums of each diagonal,
@@ -15,14 +9,14 @@ public class Path {
 	 * and use those measures to make decisions about which 
 	 * directions to move in.
 	 */
-	public static void main(String[] args) throws FileNotFoundException {
+	public static void main(String[] args) {
 		System.out.println(navigateMaxPath());
 	}
 
 
 	/** Navigate the triangle one step at a time, making decisions as we go about which direction to move. */
-	public static int navigateMaxPath() throws FileNotFoundException {
-		int[][] triangle = loadTriangle();
+	public static int navigateMaxPath() {
+		int[][] triangle = LoadTriangle.loadTriangle();
 		int dim = triangle.length;
 
 		int crawl = 0;
@@ -33,8 +27,8 @@ public class Path {
 			System.out.print(triangle[rr][cc] + " ");
 			if(rr<dim-1 && cc<dim-1) { 
 				System.out.println();
-				System.out.println("    left sum = "+subtreeSum(rr+1,cc,triangle) );
-				System.out.println("    right sum = "+subtreeSum(rr+1,cc+1,triangle) );
+				System.out.println("    left sum = " +subtriangleSum(rr+1,cc,triangle) );
+				System.out.println("    right sum = "+subtriangleSum(rr+1,cc+1,triangle) );
 			}
 
 			if(goLeft(rr,cc,triangle)) { 
@@ -50,14 +44,14 @@ public class Path {
 
 	/** Determine whether we should go left at row i, column j of the triangle. */
 	public static boolean goLeft(int i, int j, int[][] triangle) { 
-		int leftSubtreeSum  = subtriangleSum( i+1, j, triangle);
-		int rightSubtreeSum = subtriangleSum( i+1, j+1, triangle);
+		int leftSum  = subtriangleSum( i+1, j, triangle);
+		int rightSum = subtriangleSum( i+1, j+1, triangle);
 		int dim = triangle.length;
 		// break ties by value, but skip last row
-		if(leftSubtreeSum==rightSubtreeSum && i+1>dim) { 
+		if(leftSum==rightSum && i+1>dim) { 
 			return (triangle[i+1][j] > triangle[i+1][j+1]);
 		} else {
-			return leftSubtreeSum > rightSubtreeSum;
+			return leftSum > rightSum;
 		}
 	}
 
@@ -107,34 +101,4 @@ public class Path {
 	}
 
 
-	/** Load a triangle from a file. */
-	public static int[][] loadTriangle() throws FileNotFoundException {
-		int nlines = countLines();
-		int[][] triangle = new int[nlines][nlines];	
-		Scanner s = new Scanner(new BufferedReader(new FileReader(FILE)));
-		int r = 0;
-		while(s.hasNextLine()) {
-			String line = s.nextLine();
-			Scanner ls = new Scanner(line);
-			int c = 0;
-			while(ls.hasNextInt()) {
-				int num = ls.nextInt();
-				triangle[r][c] = num;
-				c++;
-			}
-			r++;
-		}
-		return triangle;
-	}
-
-	/** Count the number of lines in the triangle file. */ 
-	public static int countLines() throws FileNotFoundException { 
-		Scanner s = new Scanner(new BufferedReader(new FileReader(FILE)));
-		int lines = 0;
-		while(s.hasNextLine()) { 
-			s.nextLine();
-			lines++;
-		}
-		return lines;
-	}
 }