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Course Outline

Allow to Contest - Java Solution and Time Complexity Analysis


At a contest, children can participate only if they have ages between minAge and maxAge. Given the age of a child, check if they are allowed or not.

Example 1:

Input: minAge = 7, maxAge = 12, age =  7
Output: true

Example 2:

Input: minAge = 3, maxAge = 8, age = 10
Output: false

Understanding the Problem

The core challenge of this problem is to determine if a given age falls within a specified range. This is a common problem in scenarios where eligibility criteria are based on age, such as contests, sports events, or age-restricted activities.

Potential pitfalls include misunderstanding the inclusive nature of the age range and incorrectly implementing the boundary conditions.

Approach

To solve this problem, we can use a simple comparison to check if the given age is within the specified range. There are multiple ways to implement this:

  1. Check for invalidations and return false if the age is less than minAge or greater than maxAge, otherwise return true.
  2. Use a single if statement with two conditions to return true if the age is within the range, otherwise return false.
  3. Directly return the result of the condition as it is a boolean expression.

Algorithm

Let's break down the algorithm step-by-step:

  1. Receive the input values: minAge, maxAge, and age.
  2. Check if the age is within the range [minAge, maxAge].
  3. Return true if the age is within the range, otherwise return false.

Code Implementation

public class ContestEligibility {
    // Method to check if the child is allowed to participate
    public static boolean isAllowedToContest(int minAge, int maxAge, int age) {
        // Return the result of the condition directly
        return age >= minAge && age <= maxAge;
    }

    public static void main(String[] args) {
        // Test cases
        System.out.println(isAllowedToContest(7, 12, 7)); // true
        System.out.println(isAllowedToContest(3, 8, 10)); // false
    }
}

Complexity Analysis

The time complexity of this solution is O(1) because it involves a constant number of operations regardless of the input size. The space complexity is also O(1) as no additional space is required.

Edge Cases

Potential edge cases include:

  • When age is exactly equal to minAge or maxAge.
  • When minAge and maxAge are the same.
  • When age is outside the range.

These cases are handled by the condition age >= minAge && age <= maxAge.

Testing

To test the solution comprehensively, consider the following test cases:

  • Normal cases where age is within the range.
  • Boundary cases where age is exactly minAge or maxAge.
  • Cases where age is outside the range.

Using a testing framework like JUnit can help automate and validate these test cases.

Thinking and Problem-Solving Tips

When approaching such problems, consider the following tips:

  • Clearly understand the problem statement and constraints.
  • Break down the problem into smaller, manageable parts.
  • Think about edge cases and how to handle them.
  • Practice similar problems to improve problem-solving skills.

Conclusion

In this blog post, we discussed how to determine if a child is allowed to participate in a contest based on their age. We explored different approaches, provided a detailed algorithm, and implemented the solution in Java. Understanding and solving such problems is crucial for developing strong problem-solving skills.

Additional Resources

For further reading and practice, consider the following resources: