refactor 26

fishercoder1534 · fishercoder1534 · commit fe63f53c220b · 2019-12-29T09:26:00.000-08:00
diff --git a/src/main/java/com/fishercoder/solutions/_26.java b/src/main/java/com/fishercoder/solutions/_26.java
@@ -3,18 +3,37 @@
 /**
  * 26. Remove Duplicates from Sorted Array
  *
- * Given a sorted array, remove the duplicates
- * in place such that each element appear only once and return the new length.
- * Do not allocate extra space for another array, you must do this in place with constant memory.
+ * Given a sorted array nums, remove the duplicates in-place such that each element appear only once and return the new length.
+ * Do not allocate extra space for another array, you must do this by modifying the input array in-place with O(1) extra memory.
  *
- * For example,
- * Given input array A = [1,1,2],
- * Your function should return length = 2, and A is now [1,2].
+ * Example 1:
+ * Given nums = [1,1,2],
+ * Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively.
+ * It doesn't matter what you leave beyond the returned length.
+ *
+ * Example 2:
+ * Given nums = [0,0,1,1,1,2,2,3,3,4],
+ * Your function should return length = 5, with the first five elements of nums being modified to 0, 1, 2, 3, and 4 respectively.
+ * It doesn't matter what values are set beyond the returned length.
+ *
+ * Clarification:
+ * Confused why the returned value is an integer but your answer is an array?
+ * Note that the input array is passed in by reference, which means modification to the input array will be known to the caller as well.
+ * Internally you can think of this:
+ * // nums is passed in by reference. (i.e., without making a copy)
+ * int len = removeDuplicates(nums);
+ *
+ * // any modification to nums in your function would be known by the caller.
+ * // using the length returned by your function, it prints the first len elements.
+ * for (int i = 0; i < len; i++) {
+ *     print(nums[i]);
+ * }
  * */
 
 public class _26 {
 
   public static class Solution1 {
+    /**Key: It doesn't matter what you leave beyond the returned length.*/
     public int removeDuplicates(int[] nums) {
       int i = 0;
       for (int j = 1; j < nums.length; j++) {
@@ -26,33 +45,4 @@ public int removeDuplicates(int[] nums) {
       return i + 1;
     }
   }
-
-  public static class Solution2 {
-    /**
-     * Same idea as the editorial solution, mine just got more verbose.
-     */
-    public static int removeDuplicates(int[] nums) {
-      int i = 0;
-      for (int j = i + 1; i < nums.length && j < nums.length; ) {
-        while (j < nums.length && nums[i] == nums[j]) {
-          j++;
-        }
-        if (j == nums.length) {
-          j--;
-        }
-        int temp = nums[j];
-        nums[j] = nums[i + 1];
-        nums[i + 1] = temp;
-        if (nums[i] != nums[i + 1]) {
-          i++;
-        }
-        if (j == nums.length) {
-          break;
-        }
-        j++;
-      }
-      return i + 1;
-    }
-  }
-
 }
diff --git a/src/test/java/com/fishercoder/_26Test.java b/src/test/java/com/fishercoder/_26Test.java
@@ -7,49 +7,29 @@
 import static org.junit.Assert.assertEquals;
 
 public class _26Test {
-  private static _26.Solution1 solution1;
-  private static _26.Solution2 solution2;
-  private static int[] nums;
-
-  @BeforeClass
-  public static void setup() {
-    solution1 = new _26.Solution1();
-    solution2 = new _26.Solution2();
-  }
-
-  @Test
-  public void test1() {
-    nums = new int[] {1, 1, 2};
-    assertEquals(2, solution1.removeDuplicates(nums));
-  }
-
-  @Test
-  public void test2() {
-    nums = new int[] {1, 1, 2};
-    assertEquals(2, solution2.removeDuplicates(nums));
-  }
-
-  @Test
-  public void test3() {
-    nums = new int[] {1,1,2,2,3};
-    assertEquals(3, solution1.removeDuplicates(nums));
-  }
-
-  @Test
-  public void test4() {
-    nums = new int[] {1,1,2,2,3};
-    assertEquals(3, solution2.removeDuplicates(nums));
-  }
-
-  @Test
-  public void test5() {
-    nums = new int[] {1, 1};
-    assertEquals(1, solution1.removeDuplicates(nums));
-  }
-
-  @Test
-  public void test6() {
-    nums = new int[] {1, 1};
-    assertEquals(1, solution2.removeDuplicates(nums));
-  }
+    private static _26.Solution1 solution1;
+    private static int[] nums;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _26.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        nums = new int[]{1, 1, 2};
+        assertEquals(2, solution1.removeDuplicates(nums));
+    }
+
+    @Test
+    public void test2() {
+        nums = new int[]{1, 1, 2, 2, 3};
+        assertEquals(3, solution1.removeDuplicates(nums));
+    }
+
+    @Test
+    public void test3() {
+        nums = new int[]{1, 1};
+        assertEquals(1, solution1.removeDuplicates(nums));
+    }
 }
