When checking whether an element exists, what is the most common approach? The answer is a for or while loop. Congratulations — you’ve already learned Linear Search!
Concept
Linear Search: This algorithm visits every element to check where the element is located in the array. If the element is not found, it returns -1.
Complexity
- Time complexity: O(n)
- Space complexity: O(1)
Examples
Go
package main
import "fmt"
func linearSearch(list []int, target int) int {
for i := 0; i < len(list); i++ {
if list[i] == target {
return i
}
}
return -1
}
func main() {
fmt.Println(linearSearch([]int{1, 2, 3, 4, 5}, 3)) // 2
fmt.Println(linearSearch([]int{1, 2, 3, 4, 5}, 6)) // -1
}
C#
class Algorithm
{
public static int linearSearch(int[] list, int target)
{
for (var i = 0; i < list.Length; i++)
{
if (list[i] == target)
{
return i;
}
}
return -1;
}
public static void Main(String[] args)
{
Console.WriteLine(linearSearch(new int[] {1, 2, 3, 4, 5}, 3)); // 2
Console.WriteLine(linearSearch(new int[] {1, 2, 3, 4, 5}, 6)); // -1
}
}
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