Sequential Search (Linear Search)

Step to perform binary search:

1. Sequentially walk through the array, starting with the first element
2. Compares each element with the element we are looking for, stops when
   • The element looking for is same as the element OR
   • Reach the end of the array
3. The index of the element at the stopping position is the result

Code Sample

def sequentialSearch(arr, item):
  for i in range(len(arr)):
    if arr[i] == item:
      return i

  return -1

def sequentialSearch(arr, item):
  for i in range(len(arr)):
    if arr[i] == item:
      return i

  return -1

int sequentialSearch(int arr[], int first, int last, int key) {
  for(int index = first; index <= last; index++) {
    if(key == arr[index]) {
      return index; // found! return index
    }
  }
  return -1; // key is not found
}

Complexity Analysis

• Time complexity : ${O}(n)$