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Java Array Exercises: Find the rotation count in a given rotated sorted array of integers

Java Array: Exercise-47 with Solution

Write a Java program to find the rotation count in a given rotated sorted array of integers.

Sample Solution:

Java Code:

import java.util.*;
import java.lang.*;
import java.io.*;
 
public class Main
{
  static int count_rotations(int arr_int[], int n)
    {
       int min_val = arr_int[0], min_index = -1;
        for (int i = 0; i < n; i++)
        {
            if (min_val > arr_int[i])
            {
                min_val = arr_int[i];
                min_index = i;
            }
        } 
        return min_index;
    }
    public static void main (String[] args) 
    {
          int arr_int[] = {35, 32, 30, 14, 18, 21, 27};
      // int arr_int[] = {35, 32, 14, 18, 21, 27};
      // int arr_int[] = {35, 14, 18, 21, 27};
           int n = arr_int.length;
            System.out.println(count_rotations(arr_int, n));
    }
}

Sample Output:

                                                                              
3

Flowchart:

Flowchart: Find the rotation count in a given rotated sorted array of integers

Visualize Java code execution (Python Tutor):


Java Code Editor:

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Previous: Write a Java program to check whether there is a pair with a specified sum of a given sorted and rotated array.
Next: Write a Java program to arrange the elements of a given array of integers where all negative integers appear before all the positive integers.

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Java: Tips of the Day

Different between parseInt() and valueOf() in java?

Well, the API for Integer.valueOf(String) does indeed say that the String is interpreted exactly as if it were given to Integer.parseInt(String). However, valueOf(String) returns a new Integer() object whereas parseInt(String) returns a primitive int.

If you want to enjoy the potential caching benefits of Integer.valueOf(int), you could also use this eyesore:

Integer k = Integer.valueOf(Integer.parseInt("123"))

Now, if what you want is the object and not the primitive, then using valueOf(String) may be more attractive than making a new object out of parseInt(String) because the former is consistently present across Integer, Long, Double, etc.

Ref: https://bit.ly/3vRuIPY