Retrieve method implementation

src/main/java/NumberTriangle.java

@@ -88,8 +88,17 @@ public boolean isLeaf() {
      *
      */
     public int retrieve(String path) {
-        // TODO implement this method
-        return -1;
+        NumberTriangle current = this;
+
+        for (char direction : path.toCharArray()) {
+            if (direction == 'l') {
+                current = current.left;
+            } else if (direction == 'r') {
+                current = current.right;
+            }
+        }
+
+        return current.getRoot();
     }
 
     /** Read in the NumberTriangle structure from a file.
@@ -104,40 +113,110 @@ public int retrieve(String path) {
      * @throws IOException may naturally occur if an issue reading the file occurs
      */
     public static NumberTriangle loadTriangle(String fname) throws IOException {
-        // open the file and get a BufferedReader object whose methods
-        // are more convenient to work with when reading the file contents.
-        InputStream inputStream = NumberTriangle.class.getClassLoader().getResourceAsStream(fname);
-        BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
+        InputStream inputStream = null;
+
+        inputStream = NumberTriangle.class.getClassLoader().getResourceAsStream(fname);
+
+        if (inputStream == null) {
+            inputStream = NumberTriangle.class.getClassLoader().getResourceAsStream("resources/" + fname);
+        }
 
+        if (inputStream == null) {
+            try {
+                inputStream = new FileInputStream(fname);
+            } catch (FileNotFoundException e) {
+                // Ignore and try next approach
+            }
+        }
+
+        if (inputStream == null) {
+            try {
+                inputStream = new FileInputStream("resources/" + fname);
+            } catch (FileNotFoundException e) {
+                // Ignore and try next approach
+            }
+        }
 
-        // TODO define any variables that you want to use to store things
+        if (inputStream == null) {
+            throw new FileNotFoundException("Could not find file: " + fname +
+                    " (tried as resource, resources/" + fname + ", and as file)");
+        }
 
-        // will need to return the top of the NumberTriangle,
-        // so might want a variable for that.
-        NumberTriangle top = null;
+        BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));
 
+        int lineCount = 0;
         String line = br.readLine();
         while (line != null) {
+            lineCount++;
+            line = br.readLine();
+        }
+
+        br.close();
+
+        inputStream = NumberTriangle.class.getClassLoader().getResourceAsStream(fname);
+        if (inputStream == null) {
+            inputStream = NumberTriangle.class.getClassLoader().getResourceAsStream("resources/" + fname);
+        }
+        if (inputStream == null) {
+            try {
+                inputStream = new FileInputStream(fname);
+            } catch (FileNotFoundException e) {
+                try {
+                    inputStream = new FileInputStream("resources/" + fname);
+                } catch (FileNotFoundException e2) {
+                    throw new FileNotFoundException("File not found after reset: " + fname);
+                }
+            }
+        }
 
-            // remove when done; this line is included so running starter code prints the contents of the file
-            System.out.println(line);
+        br = new BufferedReader(new InputStreamReader(inputStream));
 
-            // TODO process the line
+        NumberTriangle[][] triangle = new NumberTriangle[lineCount][];
 
-            //read the next line
+        for (int i = 0; i < lineCount; i++) {
             line = br.readLine();
+            if (line == null) {
+                throw new IOException("Unexpected end of file at line " + i);
+            }
+            String[] numbers = line.trim().split("\\s+");
+            triangle[i] = new NumberTriangle[numbers.length];
+
+            for (int j = 0; j < numbers.length; j++) {
+                int num = Integer.parseInt(numbers[j]);
+                triangle[i][j] = new NumberTriangle(num);
+            }
         }
         br.close();
-        return top;
+
+        for (int i = 0; i < lineCount - 1; i++) {
+            for (int j = 0; j < triangle[i].length; j++) {
+                triangle[i][j].setLeft(triangle[i + 1][j]);
+                triangle[i][j].setRight(triangle[i + 1][j + 1]);
+            }
+        }
+
+        return triangle[0][0];
     }
 
     public static void main(String[] args) throws IOException {
+        NumberTriangle mt = null;
+        try {
+            mt = NumberTriangle.loadTriangle("input_tree.txt");
+        } catch (FileNotFoundException e) {
+            System.out.println("Failed to load input_tree.txt: " + e.getMessage());
+            return;
+        }
+
+        if (mt == null) {
+            System.out.println("Triangle is null after loading");
+            return;
+        }
 
-        NumberTriangle mt = NumberTriangle.loadTriangle("input_tree.txt");
+        System.out.println("Root value: " + mt.getRoot());
+        System.out.println("Left child: " + mt.retrieve("l"));
+        System.out.println("Right child: " + mt.retrieve("r"));
+        System.out.println("Left-left grandchild: " + mt.retrieve("ll"));
 
-        // [not for credit]
-        // you can implement NumberTriangle's maxPathSum method if you want to try to solve
-        // Problem 18 from project Euler [not for credit]
         mt.maxSumPath();
         System.out.println(mt.getRoot());
     }