Algocademy Logo

Course Outline

Minimum Value of Three in Python


Given 3 integers A, B and C, return the smallest number.

You are not allowed to use built-in functions such as min

Example 1:

Input: A = 7, B = 4, C = 9
Output: 4

Example 2:

Input: A = 3, B = 8, C = 3
Output: 3

Problem Definition

The problem requires us to find the smallest of three given integers A, B, and C without using built-in functions like min. The input consists of three integers, and the output should be the smallest of these integers.

Input:

  • Three integers A, B, and C.

Output:

  • The smallest integer among A, B, and C.

Constraints:

  • All inputs are integers.

Example:

Input: A = 7, B = 4, C = 9
Output: 4

Understanding the Problem

The core challenge is to determine the smallest of three numbers without using built-in functions. This problem is fundamental in understanding basic conditional statements and comparisons. It has applications in various fields such as sorting algorithms, decision-making processes, and more.

Potential Pitfalls:

  • Incorrectly comparing the numbers.
  • Not considering all possible cases.

Approach

To solve this problem, we can use conditional statements to compare the three numbers. We will start by comparing A with B and C, then B with A and C, and finally, if neither A nor B is the smallest, C will be the smallest by default.

Naive Solution:

The naive solution involves directly comparing the numbers using if-else statements. This approach is straightforward but not scalable for a larger number of values.

Optimized Solution:

An optimized approach involves using a variable to keep track of the minimum value found so far. This method is more scalable and can be easily extended to more than three numbers.

Algorithm

Step-by-Step Breakdown:

  1. Initialize a variable minVal with the value of A.
  2. Compare B with minVal. If B is smaller, update minVal to B.
  3. Compare C with minVal. If C is smaller, update minVal to C.
  4. Return minVal as the smallest number.

Code Implementation

def find_minimum(A, B, C):
    # Initialize minVal with A
    minVal = A
    
    # Compare B with minVal
    if B < minVal:
        minVal = B
    
    # Compare C with minVal
    if C < minVal:
        minVal = C
    
    # Return the smallest value
    return minVal

# Test cases
print(find_minimum(7, 4, 9))  # Output: 4
print(find_minimum(3, 8, 3))  # Output: 3

Complexity Analysis

The time complexity of this approach is O(1) because we are performing a constant number of comparisons regardless of the input size. The space complexity is also O(1) as we are using a fixed amount of extra space.

Edge Cases

Consider the following edge cases:

  • All three numbers are the same: A = 5, B = 5, C = 5. The output should be 5.
  • Two numbers are the same and the smallest: A = 2, B = 2, C = 3. The output should be 2.
  • Negative numbers: A = -1, B = -2, C = -3. The output should be -3.

Testing

To test the solution comprehensively, consider a variety of test cases:

  • Simple cases with distinct numbers.
  • Cases where two or all three numbers are the same.
  • Cases with negative numbers.

Thinking and Problem-Solving Tips

When approaching such problems, consider the following tips:

  • Break down the problem into smaller parts.
  • Use conditional statements effectively.
  • Think about edge cases and how to handle them.

Conclusion

In this blog post, we discussed how to find the minimum of three numbers without using built-in functions. We explored a naive solution and an optimized approach, provided a detailed algorithm, and analyzed the complexity. Understanding such fundamental problems is crucial for developing problem-solving skills and preparing for more complex challenges.

Additional Resources

For further reading and practice, consider the following resources: