quiz-answers.md

CSE 142

Quiz Answers

Week 6

It is important to note that these are examples of correct solutions; there are many correct solutions that will not match these solutions exactly.

1. randomWalk (15 points)

   public static void randomWalk(Random r, int goal) {
   	int pos = 0;
   	int min = 0;
   	int max = 0;
   	System.out.printf("goal = %d, pos = %d\n", goal, pos);
   	while (goal != pos) {
   		int value = r.nextInt(5) - 2;
   		pos = pos + value; 
   		System.out.printf("adding %d, pos = %d\n", value, pos);
   		if (pos < min) {
   			min = pos;
   		} else if (pos > max) {
   			max = pos;
   		}
   	}
   	System.out.printf("min = %d, max = %d\n", min, max);
   }

2. highLow (15 points)

   public static boolean highLow(int num) { 
     boolean low = num % 10 <= 4;
     while (num / 10 != 0) {
        num = num / 10;
        int digit = num % 10;
        if (digit <= 4 && low || digit > 4 && !low) {
           return false;
        }
        low = !low;
     }
     return true;
   }

3. isBalanced (9 points)

   public static boolean isBalanced(String parens) {
     int open = 0;
     int closed = 0;
     for (int i = 0; i < parens.length(); i++) {
        if (parens.charAt(i) == '(') {
           open++;
        } else {
           closed++;
        }	     
        if (closed > open) {
           return false;
        }
     }  
     return open == closed;
   }