Java Coding Test Course, Finding Minimum Value 1

Problem Definition

You have to solve the problem of finding the minimum value in a given integer array. This problem is very basic and fundamental in coding tests and algorithm problem solving, requiring basic thinking about handling arrays. Through this problem, you will practice how to use arrays and loops, as well as how to utilize conditional statements.

Problem Description

Given an integer array nums, write a function that finds and returns the minimum value in the array.

For example, if the array is [3, 1, 4, 1, 5, 9, 2, 6, 5], it should return the minimum value 1.

Input and Output Format

  • Input: Integer array nums (1 ≤ |nums| ≤ 105, -109 ≤ nums[i] ≤ 109)
  • Output: Minimum value in the array

Approach

This problem can be solved using the following approach.

  1. Check if the array is empty. If it is, handle the exception.
  2. Initialize the first element of the array as the minimum value.
  3. Iterate through the array, comparing each element with the current minimum value.
  4. If the current element is less than the minimum value, update the minimum value.
  5. After checking all elements, return the minimum value.

Detailed Solution Process

1. Check if the array is empty

First, you need to check if the provided array is empty. If it is empty, it is impossible to find the minimum value, so appropriate exception handling should be done in this case. For example, you can throw an IllegalArgumentException when the array is empty.

2. Initialize the minimum value

Set the first element of the array as the minimum value. This creates a reference point for comparing all the elements as you iterate through the array.

3. Explore the array

As you iterate through the array, compare each element with the minimum value. To find the minimum reliably, a for loop is generally used. All elements need to be checked.

4. Compare and update the minimum value

If the current element being checked is less than the minimum value, update the minimum value. This will ultimately result in having the smallest value in the array.

5. Return the minimum value

After checking all elements, return the minimum value.

Java Implementation

public class MinFinder {
    public static int findMin(int[] nums) {
        // Check for empty array
        if (nums.length == 0) {
            throw new IllegalArgumentException("The array is empty.");
        }

        // Initialize with the first element of the array
        int min = nums[0];

        // Find the minimum value while iterating through the array
        for (int i = 1; i < nums.length; i++) {
            if (nums[i] < min) {
                min = nums[i]; // Update the minimum value
            }
        }

        // Return the minimum value
        return min;
    }

    public static void main(String[] args) {
        int[] nums = {3, 1, 4, 1, 5, 9, 2, 6, 5};
        int minValue = findMin(nums);
        System.out.println("Minimum value: " + minValue); // Output: Minimum value: 1
    }
}

Time Complexity Analysis

The time complexity of this algorithm is O(n). Since we need to examine each element in the array once, it maintains a linear property concerning the size of the input. This is optimal time complexity.

Space Complexity Analysis

The space complexity of this algorithm is O(1). It uses no additional data structures and only one integer variable, so it occupies very little space.

Conclusion

Through this tutorial, you have implemented an algorithm to find the minimum value in an array. Although this problem is basic, it lays a foundation that can be expanded into more complex problems in the future. Having learned fundamental reasoning using arrays and loops, it can be beneficial for future algorithmic problems.

In the next tutorial, we will tackle more complex algorithm problems. We appreciate your anticipation.