[N-0] refactor 448

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_448.java

@@ -6,11 +6,11 @@
 import java.util.Map;
 
 /**
+ * 448. Find All Numbers Disappeared in an Array
+ *
  * Given an array of integers where 1 ≤ a[i] ≤ n (n = size of array), some elements appear twice and others appear once.
-
- Find all the elements of [1, n] inclusive that do not appear in this array.
-
- Could you do it without extra space and in O(n) runtime? You may assume the returned list does not count as extra space.
+ * Find all the elements of [1, n] inclusive that do not appear in this array.
+ * Could you do it without extra space and in O(n) runtime? You may assume the returned list does not count as extra space.
 
  Example:
 
@@ -19,75 +19,68 @@ Could you do it without extra space and in O(n) runtime? You may assume the retu
 
  Output:
  [5,6]
+
  */
 public class _448 {
 
-    /**O(n) space
-     * O(n) time*/
-    public List<Integer> findDisappearedNumbers_1(int[] nums) {
+    public static class Solution1 {
+        /**
+         * O(n) space
+         * O(n) time
+         */
+        public List<Integer> findDisappearedNumbers(int[] nums) {
 
-        int max = Integer.MIN_VALUE;
-        for (int i : nums) {
-            max = Math.max(max, i);
-        }
-        max = Math.max(max, nums.length);
-        //if using extra space is allowed, it'll be super easy as follows:
-        Map<Integer, Integer> map = new HashMap();
-        for (int i = 1; i <= max; i++) {
-            map.put(i, 0);
-        }
-
-        for (int i : nums) {
-            if (map.get(i) == 0) {
-                map.put(i, 1);
-            } else {
-                map.put(i, map.get(i) + 1);
+            int max = Integer.MIN_VALUE;
+            for (int i : nums) {
+                max = Math.max(max, i);
             }
-        }
+            max = Math.max(max, nums.length);
 
-        List<Integer> result = new ArrayList();
-        for (int i : map.keySet()) {
-            if (map.get(i) == 0) {
-                result.add(i);
+            Map<Integer, Integer> map = new HashMap();
+            for (int i = 1; i <= max; i++) {
+                map.put(i, 0);
             }
-        }
-
-        return result;
 
-    }
-
-    /**
-     * O(1) space
-     * O(n) time
-     */
-    public List<Integer> findDisappearedNumbers_2(int[] nums) {
-
-        for (int i = 0; i < nums.length; i++) {
-            int val = Math.abs(nums[i]) - 1;
-            if (nums[val] > 0) {
-                nums[val] = -nums[val];
+            for (int i : nums) {
+                if (map.get(i) == 0) {
+                    map.put(i, 1);
+                } else {
+                    map.put(i, map.get(i) + 1);
+                }
             }
-        }
 
-        List<Integer> result = new ArrayList();
-        for (int i = 0; i < nums.length; i++) {
-            if (nums[i] > 0) {
-                result.add(i + 1);
+            List<Integer> result = new ArrayList();
+            for (int i : map.keySet()) {
+                if (map.get(i) == 0) {
+                    result.add(i);
+                }
             }
+            return result;
         }
-
-        return result;
-
     }
 
-    public static void main(String... args) {
-        _448 test = new _448();
-//        int[] nums = new int[]{4,3,2,7,8,2,3,1};
-        int[] nums = new int[]{1, 1};
-        List<Integer> result = test.findDisappearedNumbers_2(nums);
-        for (int i : result) {
-            System.out.println(i);
+    public static class Solution2 {
+        /**
+         * O(1) space
+         * O(n) time
+         */
+        public List<Integer> findDisappearedNumbers_2(int[] nums) {
+
+            for (int i = 0; i < nums.length; i++) {
+                int val = Math.abs(nums[i]) - 1;
+                if (nums[val] > 0) {
+                    nums[val] = -nums[val];
+                }
+            }
+
+            List<Integer> result = new ArrayList();
+            for (int i = 0; i < nums.length; i++) {
+                if (nums[i] > 0) {
+                    result.add(i + 1);
+                }
+            }
+            return result;
         }
     }
 
-}
+}