Create RotateArray.java

Java/RotateArray.java

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+/******************************************************************************
+189.) Rotate Array 
+Difficulty: Medium
+Description: Given an array, rotate the array to the right by k steps, where k is non-negative.
+
+Naive Approach: Create a function that rotates the array onces, then rotate the array k times.
+Efficient Approach: Reverse the whole list, then reverse the first k elements, and the last n - k elements. 
+*******************************************************************************/
+
+public class RotateArray
+{
+	public static void main(String[] args) {
+
+		/* This is the test, expected output is [4,5,1,2,3] */
+
+		int [] arr = {1,2,3,4,5};
+
+		rotate(arr, 2);
+
+		int[] rotate_arr = arr;
+
+		for(int i = 0; i < rotate_arr.length; i++){
+		    System.out.print(rotate_arr[i] + " ");
+		}
+
+	}
+
+	 public static void rotate(int[] nums, int k) {
+        k = k % nums.length;
+
+
+        reverse(nums, 0, nums.length - 1);
+        reverse(nums, 0, k-1);
+        reverse(nums, k, nums.length - 1); 
+    }
+
+    public static int [] reverse(int [] nums, int start, int end){
+        int indx_end = end, indx_start = start;
+
+        while(indx_start < indx_end){
+            int temp = nums[indx_start];
+            nums[indx_start] = nums[indx_end];
+            nums[indx_end] = temp;
+            indx_start++;
+            indx_end--;
+
+            }
+
+        return nums;
+
+    }
+}
+
+
+