Allow to Contest - JavaScript 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 content.

Potential pitfalls include misunderstanding the inclusive nature of the age range or incorrectly implementing the boundary checks.

Approach

To solve this problem, we need to check if the given age is within the inclusive range defined by minAge and maxAge. There are several ways to approach this:

Naive Solution

A naive solution would involve checking if the age is less than minAge or greater than maxAge and returning false in those cases. Otherwise, return true. This approach is straightforward but can be optimized.

Optimized Solutions

1. Using a single if statement with two conditions.

2. Directly returning the boolean result of the condition check.

Algorithm

Let's break down the steps for each approach:

Naive Approach

function isAllowedToContest(minAge, maxAge, age) {
  // Check if age is less than minAge or greater than maxAge
  if (age < minAge || age > maxAge) {
    return false;
  }
  return true;
}

Optimized Approach 1

function isAllowedToContest(minAge, maxAge, age) {
  // Use a single if statement with two conditions
  if (age >= minAge && age <= maxAge) {
    return true;
  }
  return false;
}

Optimized Approach 2

function isAllowedToContest(minAge, maxAge, age) {
  // Directly return the boolean result of the condition check
  return age >= minAge && age <= maxAge;
}

Complexity Analysis

All the approaches have a time complexity of O(1) because they involve 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

Consider the following edge cases:

Age is exactly equal to minAge or maxAge.
Age is less than minAge or greater than maxAge.
Age is within the range but very close to the boundaries.

Each algorithm handles these edge cases effectively by checking the inclusive range.

Testing

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

console.log(isAllowedToContest(7, 12, 7)); // true
console.log(isAllowedToContest(3, 8, 10)); // false
console.log(isAllowedToContest(5, 10, 5)); // true
console.log(isAllowedToContest(5, 10, 10)); // true
console.log(isAllowedToContest(5, 10, 4)); // false
console.log(isAllowedToContest(5, 10, 11)); // false

Thinking and Problem-Solving Tips

When approaching such problems, consider the following tips:

Understand the problem requirements and constraints thoroughly.
Break down the problem into smaller, manageable parts.
Consider edge cases and how your solution handles them.
Optimize your solution by reducing unnecessary checks or operations.

Conclusion

In this blog post, we discussed how to determine if a child's age falls within a specified range using JavaScript. We explored multiple approaches, analyzed their complexities, and provided comprehensive testing strategies. Understanding and solving such problems is crucial for developing strong problem-solving skills.

Additional Resources

For further reading and practice, consider the following resources: