Linear Search
static int Linear-search(int array[], int array-size, int Element-to-search)
{
for (int i = 0; i < array-size; i++)
{
// Return the index of the element if the element
// is found
if (arr[i] == x)
return i;
}
// return -1 if the element is not found
return -1;
}
The time complexity of above algorithm is O(n)
Q ) Search Element in unsorted Array
sol :-
using System;
class GFG
{
public static int search(int[] arr, int x)
{
int n = arr.Length;
for(int i = 0; i < n; i++)
{
if(arr[i] == x)
return i;
}
return -1;
}
public static void Main()
{
int[] arr = { 2, 3, 4, 10, 40 };
int x = 10;
int result = search(arr, x);
if(result == -1)
Console.WriteLine("Element is not present in array");
else
Console.WriteLine("Element is present at index "+ result);
}
}
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Binary Search
Below are the Iterative implementation of Binary Search :-
static int Binary-Search(int array[], int Element-to-Search)
{
int low = 0, high = arr.length - 1;
//low is first index of array and high is last index of array
while (low <= high)
{
int mid = l ow+ (high - low) / 2; // Formula to find the mid point
// Check if Element-to-Search is present at mid
if (array[mid] == Element-to-Search)
return mid;
// If Element-to-Search greater, ignore left half
if (array[mid] < Element-to-Search)
low = mid + 1;
// If Element-to-Search is smaller, ignore right half
else
high = mid - 1;
}
// if we reach here, then element was
// not present
return -1;
}
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Recursive implementation of Binary Search
static int binary-Search (int array[], int low, int high, int Element)
{
if (low <= high)
{
int mid = l ow+ (high - low) / 2;
// If the element is present at the
// middle itself
if (array[mid] == Element)
return mid;
// If element is smaller than mid, then
// it can only be present in left subarray
if (array[mid] > Element)
return binarySearch(array, low, mid - 1, Element);
// Else the element can only be present
// in right subarray
return binarySearch(array, mid + 1, high, Element);
}
// We reach here when element is not present
// in array
return -1;
}
