tests passed: implemented loadTriangle and retrieve successfully

src/main/java/NumberTriangle.java

@@ -1,4 +1,6 @@
 import java.io.*;
+import java.util.*;
+
 
 /**
  * This is the provided NumberTriangle class to be used in this coding task.
@@ -87,11 +89,26 @@ public boolean isLeaf() {
      * @return the root value at the location indicated by path
      *
      */
+
     public int retrieve(String path) {
-        // TODO implement this method
-        return -1;
+        NumberTriangle cur = this;
+        for (int i = 0; i < path.length(); i++) {
+            char c = path.charAt(i);
+            if (c == 'l') {
+                cur = cur.left;
+            } else if (c == 'r') {
+                cur = cur.right;
+            } else {
+                throw new IllegalArgumentException("Invalid path char: " + c);
+            }
+            if (cur == null) {
+                throw new IndexOutOfBoundsException("Path goes past the triangle at index " + i);
+            }
+        }
+        return cur.root;
     }
 
+
     /** Read in the NumberTriangle structure from a file.
      *
      * You may assume that it is a valid format with a height of at least 1,
@@ -110,7 +127,7 @@ public static NumberTriangle loadTriangle(String fname) throws IOException {
         BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
 
 
-        // TODO define any variables that you want to use to store things
+        List<List<Integer>> rows = new ArrayList<>();
 
         // will need to return the top of the NumberTriangle,
         // so might want a variable for that.
@@ -119,14 +136,45 @@ public static NumberTriangle loadTriangle(String fname) throws IOException {
         String line = br.readLine();
         while (line != null) {
 
-            // remove when done; this line is included so running starter code prints the contents of the file
-            System.out.println(line);
+            // System.out.println(line);
+
+            line = line.trim();
+            if (!line.isEmpty()) {
+                String[] parts = line.split("\\s+");
+                List<Integer> row = new ArrayList<>();
+                for (String p : parts) {
+                    row.add(Integer.parseInt(p));
+                }
+                rows.add(row);
+            }
 
-            // TODO process the line
 
             //read the next line
             line = br.readLine();
         }
+
+
+        List<NumberTriangle> prevRow = new ArrayList<>();
+        List<Integer> lastRow = rows.get(rows.size() - 1);
+        for (int n : lastRow) {
+            prevRow.add(new NumberTriangle(n));
+        }
+
+        for (int i = rows.size() - 2; i >= 0; i--) {
+            List<Integer> current = rows.get(i);
+            List<NumberTriangle> newRow = new ArrayList<>();
+            for (int j = 0; j < current.size(); j++) {
+                NumberTriangle node = new NumberTriangle(current.get(j));
+                node.setLeft(prevRow.get(j));
+                node.setRight(prevRow.get(j + 1));
+                newRow.add(node);
+            }
+            prevRow = newRow;
+        }
+
+        top = prevRow.get(0);
+
+
         br.close();
         return top;
     }