Completed Java Assignment 09

README.md

@@ -16,7 +16,7 @@
     * Is the **blank** object mutable or immutable? How can you tell?
 
 ```text
-PUT ANSWER TO #2 HERE
+The point object is immutable. the p.x and p.y are accessed but not modified. the method will return a new value based on x, p.x, or p.y, it doesnt modify p by itself.
 ```
 
 ```java
@@ -47,7 +47,7 @@ public class Puzzler {
     * Explain how the return values from #3 and #4 differ.
 
 ```text
-PUT ANSWER TO #5 HERE
+findCenter returns a point that represents a location, while distance returns a double that is a numerical value
 ```
 
 ```java
@@ -87,14 +87,15 @@ Recall that aliases are two variables that refer to the same object.
     * Put the output in the text block below
 
 ```text
-PUT ANSWER TO #2 HERE
+(5, 8)
+(6, 9)
 ```
 
 3. At the end of main, are p1 and p2 aliased? Why or why not?
     * Put your answer in the text block below
 
 ```text
-PUT ANSWER TO #3 HERE
+p1 and p2 arent aliased because aliasing refers to atleast 2 variables referring to the same object in memory. p1 and p2 refer to completely different point objects.
 ```
 
 ```java

src/BigIntRewrite.java

@@ -1,5 +1,23 @@
+import java.math.BigInteger;
+
 public class BigIntRewrite {
-    public static void main(String[] args) {
+    public static BigInteger pow(int x, int n) {
+        if (n == 0) return BigInteger.ONE;
+        // find x to the n/2 recursively
+        BigInteger t = pow(x, n / 2);
+        // if n is even, the result is t squared
+        // if n is odd, the result is t squared times x
+        if (n % 2 == 0) {
+            return t.multiply(t);
+        } else {
+            return t.multiply(t).multiply(BigInteger.valueOf(x));
+        }
+    }
 
+    public static void main(String[] args) {
+        int x = 2;
+        int n = 10;
+        BigInteger result = pow(x, n);
+        System.out.println(x + " raised to the power of " + n + " is " + result);
     }
 }

src/StringPlayground.java

@@ -1,4 +1,34 @@
+import java.util.Stack;
+
 public class StringPlayground {
+
+    public static boolean checkBalancedBrackets(String s) {
+        Stack<Character> stack = new Stack<>();
+        for (char c : s.toCharArray()) {
+            if (c == '(' || c == '[' || c == '{') {
+                stack.push(c);
+            } else if (c == ')' || c == ']' || c == '}') {
+                if (stack.isEmpty()) {
+                    return false;
+                }
+                char top = stack.pop();
+                if ((c == ')' && top != '(') || (c == ']' && top != '[') || (c == '}' && top != '{')) {
+                    return false;
+                }
+            }
+        }
+        return stack.isEmpty();
+    }
+
     public static void main(String[] args) {
+        String s1 = "{[()]}";
+        String s2 = "{[(])}";
+        String s3 = "([)]";
+        String s4 = "((()))";
+
+        System.out.println("Is s1 balanced? " + checkBalancedBrackets(s1));
+        System.out.println("Is s2 balanced? " + checkBalancedBrackets(s2));
+        System.out.println("Is s3 balanced? " + checkBalancedBrackets(s3));
+        System.out.println("Is s4 balanced? " + checkBalancedBrackets(s4));
     }
-}
+}