searchAlgorithms

searchAlgorithms.js

const binarySearch = (array, value) => {
  /**
   * 1. Define a midPoint variable
   * 2. Define and initialize min and max index variables
   * 3. Perform a loop through the array
   * 4. Assign the mid index of the array to the midPoint variable
   * 5. Compare the current midPoint value with search value
   * 6. Return value if midPoint value === search value
   * 7. Reassign the min index if the midPoint val < search val
   * 8. Reassign the max index if the midPoint val > search val
   * 9. Return -1 if search val !found
   */
  let midPoint,
    min = 0,
    max = array.length - 1;
  while (min <= max) {
    midPoint = Math.floor((min + max) / 2);
    if (array[midPoint] === value) {
      return array[midPoint];
    } else if (array[midPoint] < value) {
      min = midPoint + 1;
    } else {
      max = midPoint - 1;
    }
  }
  return -1;
}

binarySearch([1, 2, 3, 4, 5, 6, 7, 8, 9], 20); // -1
binarySearch([1, 2, 3, 4, 5, 6, 7, 8, 9], 4); // 4


const linearSearch = (list, searchItem) => {
  for(let i = 0; i < list.length; i++) {
    if(list[i] === searchItem) {
      return list.indexOf(searchItem);
    }
    return -1;
  }
};

const arr = ['a', 'd', 'k', 'b', 'e', 'i', 'm']
linearSearch(arr, 'e');