readme.md

Linear Search

Linear search is a sequential searching algorithm where we start from one end and check every element of the list until the desired element is found. It is the simplest searching algorithm. Referfor better undeerstanding.

Complexity

Best	Worst	Memory
1	n	1

Pseudo Code

LinearSearch( A : Array of items, Target : item to be searched)
    for each i item in the array:
        if item == target
            return index i     // Returns the index at wich the element is present

    else return -1             // Denotes element is not present in that array.

Implementation

• C++
• Python
• C
• Java
• Javascript
• Go
• Ruby
• C#
• PHP

C++

    int linearSearch(vector<int> v , int target){

        for(int i = 0; i < v.size(); i++){
            if(v[i] == target){
                return i;
            }
        }

        return -1;
    }

Python

def linearSearch(Array,target):
	for i in range(0,len(Array)):
	    if Array[i] == target:
		return i
	
	return -1

C

int linearSearch(int array[],int target){

int size = sizeof(array)/sizeof(int);

for(int i = 0; i < size; i++){
    if(array[i] == target) {
	return i;
    }
}

return -1;
}

Java

public class Main {
	public static int linearSearch(int array [], int target){
	int size = array.length;
	
	for(int i = 0; i < size;i++){
	
	    if(array[i] == target){
		return i;
	    }
	}
	
	return -1;
	}
}

Javascript

const linearSearch = (list, item) => {
for (const [i, element] of list.entries()) {
    if (element === item) {
    return i
    }
}
return -1
}

Go

func linearSearch(array []int, target int){
size := len(array)

for i := 0; i < size; i++{
    if array[i] == target {
	return i
    }
}

return -1
}

C# (C SHARP)

// C# Recursive Code For Linear Search
using System;

static class Test {
	static int[] arr = { 5, 15, 6, 9, 4 };

	// Recursive Method to search key in the array
	static int linearsearch(int[] arr, int size, int key)
	{
		if (size == 0) {
			return -1;
		}
		else if (arr[size - 1] == key) {
			// Return the index of found key.
			return size - 1;
		}
		else {
			return linearsearch(arr, size - 1, key);
		}
	}

	// Driver method
	public static void Main(String[] args)
	{
		int key = 4;

		// Method call to find key
		int index = linearsearch(arr, arr.Length, key);

		if (index != -1)
			Console.Write("The element " + key
						+ " is found at " + index
						+ " index of the given array.");
		else
			Console.Write("The element " + key
						+ " is not found.");
	}
}

Output:

The element 4 is found at 4 index of the given array.

The time Complexity: O(N)

Auxiliary Space: O(N), for using recursive stack space.

Ruby

def linear_search(array, element)
  i = 0
  while i < array.length
      if array[i] == element
        return "#{element} at index #{array.index(element)}"
      end
      i+=1
    end
    return -1
end

PHP

// Recursive function to search key in the array
function linearsearch($arr, int $size, int $x)
{
    if ($size == 0)
        return -1;
    else if ($arr[$size - 1] == $x)
        return $size - 1; // return index
    return linearsearch($arr, $size - 1, $x);
}