Finished Arrays Sieve

arrays/src/arrays/Main.java

@@ -19,49 +19,16 @@ class Sieve implements Iterator<Integer> {
         this.lim = lim;
         this.isntPrime = new boolean[lim + 1];
 
-        int i = 2;
-        while (i < this.lim) {
-            for (int j = i; j < this.lim; j += i) {
-                System.out.println(j);
-                this.isntPrime[j] = true;
+        for (int i = 2; i <= lim; i++)
+            if (!isntPrime[i]) {
+                int mult = i + i; // Start with next multiple of i.
+                while (mult <= lim) {
+                    isntPrime[mult] = true;
+                    mult += i;
                 }
-            this.isntPrime[i] = false;
-            while (i < this.lim && this.isntPrime[i]) i++;
             }
-
-        /*
-        this.isntPrime[4] = true;
-        this.isntPrime[6] = true;
-        this.isntPrime[8] = true;
-        this.isntPrime[9] = true;
-        this.isntPrime[10] = true;
-        this.isntPrime[12] = true;
-        this.isntPrime[14] = true;
-        this.isntPrime[15] = true;
-        this.isntPrime[16] = true;
-        this.isntPrime[18] = true;
-        this.isntPrime[20] = true;
-        this.isntPrime[21] = true;
-        this.isntPrime[22] = true;
-        this.isntPrime[24] = true;
-        this.isntPrime[25] = true;
-        this.isntPrime[26] = true;
-        this.isntPrime[27] = true;
-        this.isntPrime[28] = true;
-        */
-
-        /*
-        for (int i = this.cur; i <= this.lim; i += this.cur) {
-            this.isntPrime[i] = true;
     }
 
-        for (int i = this.cur; !this.isntPrime[i]; i++) {}
-        */
-    }
-
-    // [ false false true  true  false true false  true ]
-    // [ 0     1     2     3     4     5     6     7 ]
-
     public boolean hasNext() { return this.cur < this.lim; }
 
     public Integer next() {
@@ -79,6 +46,7 @@ class Examples {
         t.checkExpect(sieve.next(), 5);
         t.checkExpect(sieve.next(), 7);
         t.checkExpect(sieve.next(), 11);
+        t.checkExpect(sieve.hasNext(), true);
         t.checkExpect(sieve.next(), 13);
         t.checkExpect(sieve.next(), 17);
         t.checkExpect(sieve.next(), 19);

traversal/src/traversal/Main.java

@@ -178,7 +178,6 @@ class BFT<X> implements Iterator<X> {
     }
 }
 
-/*
 class TreeFinder {
     // Know the first element of the preorder list will be the root node of the
     // tree. Assuming node values are unique, you can then locate that node in
@@ -186,6 +185,7 @@ class TreeFinder {
     // subtree, the ones to the right on the right. Repeat the process on the
     // subtreees.
 
+    // Learned you can do static methods with a type like this :).
     static <T> BT<T> find(ArrayList<T> inorder, ArrayList<T> preorder) {
         int inorderRootIdx = inorder.indexOf(preorder.getFirst());
         System.out.println(inorderRootIdx);
@@ -238,7 +238,6 @@ class TreeFinder {
         return new Node<>(val, leftTree, rightTree);
     }
 }
-*/
 
 class Examples {
     BT<Integer> tree;
@@ -298,7 +297,6 @@ class Examples {
         );
     }
 
-    /*
     void testTreeFinder(Tester t) {
         init();
 
@@ -315,5 +313,4 @@ class Examples {
 
         t.checkExpect(found, tree);
     }
-    */
 }