zillow

Question 1) 
Given a string, write a routine that converts the string to a long, without using the
built in functions that would do this. Describe what (if any) limitations the code has. For
example:
     long stringToLong(String s)
     {
          /* code goes here to convert a string to a long */
     }
     void test()
     {
          long i = stringToLong("123");
          if (i == 123)
          // success
          else
          // failure
     }

/*
     * Complete the function below.
     */
    static long parseLong(String str) throws Exception {
        if (str == null || str.length() == 0) {
             throw new Exception("Invalid number.");
        }
        long result = 0;
        int len = str.length();
        boolean isPositive = true;
        int start = 0; // first number

        // check sign
        if (str.charAt(start) == '+') {
            isPositive = true;
            start++;
        } else if (str.charAt(start) == '-') {
            isPositive = false;
            start++;
        }

        // check if valid
        if (start == len || (str.charAt(start) == '0' && start != len - 1)) {
            throw new Exception("Invalid number.");
        }

        for (int i = start; i < len; i++) {
            char c = str.charAt(i);
            if (c >= '0' && c <= '9') {
                if (result > Long.MAX_VALUE / 10) {
                    throw new Exception("Number overflow.");
                }
                if (result == Long.MAX_VALUE / 10 && i == len - 1) {
                    if (isPositive && c > '7') {
                        throw new Exception("Number overflow.");
                    } else if (!isPositive && c > '8') {
                        throw new Exception("Number Overflow.");
                    } else if (!isPositive && c == '8') {
                        return Long.MIN_VALUE;
                    }
                }
                result = result * 10;
                result += (long) (c - '0');
            } else {
                throw new Exception("Invalid number.");
            }
        }

        return result;
    }

Question 2) Implement insert and delete in a tri-nary tree. A tri-nary tree is much like a binary
tree but with three child nodes for each parent instead of two -- with the left node being values
less than the parent, the right node values greater than the parent, and the middle nodes values
equal to the parent.

For example, suppose I added the following nodes to the tree in this order: 5, 4, 9, 5, 7, 2, 2.
The resulting tree would look like this:
    5
  / | \
 4  5  9
 /     /
 2   7
 | 
 2


 /* PLEASE DO NOT UNCOMMENT THIS BLOCK

import java.io.IOException;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.util.*;
// No other imports are permitted

// The following definitions of Tree and Node are provided.
// insert and delete will be methods of class Tree.

public class Tree {
    private class Node {
        private int val;
        private Node left = null;
        private Node right = null;
        private Node mid = null;

        public Node(int val) {
            this.val = val;
        }
    }

    private Node root; 
*/

    /*
     * Please complete this method.
     * Inserts val into the tree.
     */
    public void insert(int val) {
        if (root == null) {
            root = new Node(val);
            return;
        }

        insert(root, val);
    }

    private void insert(Node root, int val) {
        if (root == null) {
            return;
        } else if (root.val == val) {
            Node curr = root;
            while (curr.mid != null) {
                curr = curr.mid;
            }
            curr.mid = new Node(val);
        } else if (root.val > val) {
            if (root.left != null) {
                insert(root.left, val);
            } else {
                root.left = new Node(val);
            }
        } else if (root.val < val) {
            if (root.right != null) {
                insert(root.right, val);
            } else {
                root.right = new Node(val);
            }
        }
    }

    /*
     * Please complete this method.
     * Deletes only one instance of val from the tree.
     * If val does not exist in the tree, do nothing.
     */
    public void delete(int val) {
        root = delete(root, val);
    }

    private Node delete(Node root, int val) {
        if (root == null) {
            return root;
        }
        if (root.val == val) {
            // delete mid
            if (root.mid != null) {
                root.mid = delete(root.mid, val);
            } else if (root.right != null) {
                // get most left-bottom one from right subtree
                Node curr = root.right;
                while (curr.left != null) {
                    curr = curr.left;
                }. from: 1point3acres.com/bbs 
                int smallest = curr.val;
                root.val = smallest;
                root.right = delete(root.right, smallest);
            } else { // replace root with it's left
                root = root.left;
            }
        } else if (root.val > val) {
            root.left = delete(root.left, val); 
        } else if (root.val < val) {
            root.right = delete(root.right, val);
        }

        return root;
    }

Question 3） Nth fib

Question 4）css