refactor 189

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_189.java

@@ -1,89 +1,64 @@
 package com.fishercoder.solutions;
 
-/**
- * 189. Rotate Array
-
- Given an array, rotate the array to the right by k steps, where k is non-negative.
-
- Example 1:
- Input: [1,2,3,4,5,6,7] and k = 3
- Output: [5,6,7,1,2,3,4]
- Explanation:
- rotate 1 steps to the right: [7,1,2,3,4,5,6]
- rotate 2 steps to the right: [6,7,1,2,3,4,5]
- rotate 3 steps to the right: [5,6,7,1,2,3,4]
-
- Example 2:
- Input: [-1,-100,3,99] and k = 2
- Output: [3,99,-1,-100]
- Explanation:
- rotate 1 steps to the right: [99,-1,-100,3]
- rotate 2 steps to the right: [3,99,-1,-100]
-
- Note:
- Try to come up as many solutions as you can, there are at least 3 different ways to solve this problem.
- Could you do it in-place with O(1) extra space?
- * */
-
 public class _189 {
 
-  public static class Solution1 {
-    /**
-     * O(n*k) time
-     * O(1) space
-     */
-    public void rotate(int[] nums, int k) {
-      int tmp;
-      for (int i = 0; i < k; i++) {
-        tmp = nums[nums.length - 1];
-        for (int j = nums.length - 1; j > 0; j--) {
-          nums[j] = nums[j - 1];
+    public static class Solution1 {
+        /**
+         * O(n*k) time
+         * O(1) space
+         */
+        public void rotate(int[] nums, int k) {
+            int tmp;
+            for (int i = 0; i < k; i++) {
+                tmp = nums[nums.length - 1];
+                for (int j = nums.length - 1; j > 0; j--) {
+                    nums[j] = nums[j - 1];
+                }
+                nums[0] = tmp;
+            }
         }
-        nums[0] = tmp;
-      }
     }
-  }
 
-  public static class Solution2 {
-    /**
-     * using an extra array of the same size to copy it
-     * O(n) time
-     * O(n) space
-     */
-    public void rotate(int[] nums, int k) {
-      int len = nums.length;
-      int[] tmp = new int[len];
-      for (int i = 0; i < len; i++) {
-        tmp[(i + k) % len] = nums[i];
-      }
-      for (int i = 0; i < len; i++) {
-        nums[i] = tmp[i];
-      }
+    public static class Solution2 {
+        /**
+         * using an extra array of the same size to copy it
+         * O(n) time
+         * O(n) space
+         */
+        public void rotate(int[] nums, int k) {
+            int len = nums.length;
+            int[] tmp = new int[len];
+            for (int i = 0; i < len; i++) {
+                tmp[(i + k) % len] = nums[i];
+            }
+            for (int i = 0; i < len; i++) {
+                nums[i] = tmp[i];
+            }
+        }
     }
-  }
 
-  public static class Solution3 {
-    /**
-     * reverse three times
-     * O(n) time
-     * O(1) space
-     */
-    public void rotate(int[] nums, int k) {
-      int len = nums.length;
-      k %= len;
-      reverse(nums, 0, len - 1);
-      reverse(nums, 0, k - 1);
-      reverse(nums, k, len - 1);
-    }
+    public static class Solution3 {
+        /**
+         * reverse three times
+         * O(n) time
+         * O(1) space
+         */
+        public void rotate(int[] nums, int k) {
+            int len = nums.length;
+            k %= len;
+            reverse(nums, 0, len - 1);
+            reverse(nums, 0, k - 1);
+            reverse(nums, k, len - 1);
+        }
 
-    private void reverse(int[] nums, int start, int end) {
-      while (start < end) {
-        int tmp = nums[start];
-        nums[start] = nums[end];
-        nums[end] = tmp;
-        start++;
-        end--;
-      }
+        private void reverse(int[] nums, int start, int end) {
+            while (start < end) {
+                int tmp = nums[start];
+                nums[start] = nums[end];
+                nums[end] = tmp;
+                start++;
+                end--;
+            }
+        }
     }
-  }
 }