Linear Search

Linear Search is a straightforward algorithm for finding a specific element in a list. It sequentially checks each element until the target is found or the list ends, making it simple and effective for unsorted data but inefficient for large datasets.

/**
 * @file Linear Search
 * @author Dustin Boston
 * @see Cormen, T, Leiserson, C, Rivest, R, and Stein, C. (2001).
 *   Introduction to Algorithms. (2nd ed). The MIT Press.
 */

/**
 * @param list - The array of elements to search through.
 * @param target - The element being searched for.
 * @returns The index of the target if found, or null if not found.
 * @see Introduction to Algorithms, 2nd Ed, Chapter on Basic Searching Algorithms
 */
export function linearSearch<T>(list: T[], target: T): number | undefined {
  for (const [index, element] of list.entries()) {
    if (element === target) {
      return index; // Target found, return the index.
    }
  }

return undefined;
}

(() => {
  // Test case 1: Should return the index of a value.
  const numbers1 = [5, 2, 4, 6, 1, 3];
  const result1 = linearSearch(numbers1, 6);
  if (result1 !== 3) {
    throw new Error(`Test failed: expected 3 but got ${result1}`);
  }

console.log('Test passed: value 6 found at index 3.');

// Test case 2: Should return null if the value isn't found.
  const numbers2 = [31, 41, 59, 26, 41, 58];
  const result2 = linearSearch(numbers2, 6);
  if (result2 !== null) {
    throw new Error(`Test failed: expected null but got ${result2}`);
  }

console.log('Test passed: value 6 not found.');
})();