refactor 251

fishercoder1534 · fishercoder1534 · commit d55fe436d9b8 · 2018-10-27T08:35:53.000-07:00
diff --git a/src/main/java/com/fishercoder/solutions/_251.java b/src/main/java/com/fishercoder/solutions/_251.java
@@ -5,58 +5,34 @@
 import java.util.List;
 import java.util.Queue;
 
-/**Implement an iterator to flatten a 2d vector.
-
- For example,
- Given 2d vector =
-
- [
- [1,2],
- [3],
- [4,5,6]
- ]
- By calling next repeatedly until hasNext returns false, the order of elements returned by next should be: [1,2,3,4,5,6].
-
- Hint:
-
- How many variables do you need to keep track?
- Two variables is all you need. Try with x and y.
- Beware of empty rows. It could be the first few rows.
- To write correct code, think about the invariant to maintain. What is it?
- The invariant is x and y must always point to a valid point in the 2d vector. Should you maintain your invariant ahead of time or right when you need it?
- Not sure? Think about how you would implement hasNext(). Which is more complex?
- Common logic in two different places should be refactored into a common method.
-
- Follow up:
- As an added challenge, try to code it using only iterators in C++ or iterators in Java.*/
-
 public class _251 {
 
-    class Vector2D implements Iterator<Integer> {
-        private Queue<Integer> cache;
-        private List<List<Integer>> vec2d;
-
-        public Vector2D(List<List<Integer>> vec2d) {
-            this.vec2d = vec2d;
-            this.cache = new LinkedList<Integer>();
-            if (vec2d != null && vec2d.size() > 0) {
-                for (List<Integer> list : vec2d) {
-                    for (int i : list) {
-                        cache.offer(i);
+    public static class Solution1 {
+        class Vector2D implements Iterator<Integer> {
+            private Queue<Integer> cache;
+            private List<List<Integer>> vec2d;
+
+            public Vector2D(List<List<Integer>> vec2d) {
+                this.vec2d = vec2d;
+                this.cache = new LinkedList<Integer>();
+                if (vec2d != null && vec2d.size() > 0) {
+                    for (List<Integer> list : vec2d) {
+                        for (int i : list) {
+                            cache.offer(i);
+                        }
                     }
                 }
             }
-        }
 
-        @Override
-        public Integer next() {
-            return cache.poll();
-        }
+            @Override
+            public Integer next() {
+                return cache.poll();
+            }
 
-        @Override
-        public boolean hasNext() {
-            return !cache.isEmpty();
+            @Override
+            public boolean hasNext() {
+                return !cache.isEmpty();
+            }
         }
     }
-
 }
