Binary Search Algorithm

Binary search

int binarySearch(int low,int high,int key)
{
   while(low<=high)
   {
     int mid=(low+high)/2;
     if(a[mid]<key)
     {
         low=mid+1;
     }
     else if(a[mid]>key)
     {
         high=mid-1;
     }
     else
     {
         return mid;
     }
   }
   return -1;                //key not found
 }

Source: hackerearth.com

Binary Search Algorithm

/*
Java Implementation of Binary Search Algorithm.
- Assuming the Array is Sorted (Ascending Order)
- returns the Index, if Element found.
- -1, if not found.
*/
public class BinarySearch {

    int binarysearch(int[] array, int element) {
        int a_pointer = 0;
        int b_pointer = array.length -1;
      	if (array[a_pointer] == element) return a_pointer;
        if (array[b_pointer] == element) return b_pointer;

        while(a_pointer <= b_pointer){
            int midpoint = a_pointer + (b_pointer - a_pointer) / 2;
          	if (array[midpoint] == element) return midpoint;
          
          	// ignoring the left half, if this is True.
            if (array[midpoint] < element) a_pointer = midpoint + 1;
          
          	// ignoring the right half, if this is True.
            else if (array[midpoint] > element) b_pointer = midpoint - 1;
        }
        return -1;	// Element not Found
    }
    public static void main(String[] args) {
        int[] list = {1, 2, 3, 4, 7, 9, 11, 12, 15, 19, 23, 36, 54, 87};
        System.out.println(binarysearch(list, 19));
    }
}

Implement a binary search of a sorted array of integers Using pseudo-code.

# Here's the pseudocode for binary search, modified for searching in an array. The inputs are the array, which we call array; the number n of elements in array; and target, the number being searched for. The output is the index in array of target:

    1.Let min = 0 and max = n-1.
    2. Compute guess as the average of max and min, rounded down (so that it is an integer).
    3. If array[guess] equals target, then stop. You found it! Return guess.
    4. If the guess was too low, that is, array[guess] < target, then set min = guess + 1.
    5. Otherwise, the guess was too high. Set max = guess - 1.
    6. Go back to step 2.

Binary search algorithm

#include <bits/stdc++.h>

using namespace std;

int binarySearch(int arr[], int l, int h, int key){
    if(l<=h){
        int mid = l + (h-l)/2;

        if(arr[mid] == key){
            return mid;
        }

        else if(arr[mid] > key){
            return binarySearch(arr, l, mid-1, key);
        }

        else if(arr[mid] < key){
            return binarySearch(arr,mid+1, h, key);
        }
    }       

    return -1;
}

int main(){
    int arr[] = {1,2,3,4,5,6,7,8,9,10};
    int n = sizeof(arr)/sizeof(arr[0]);
    int key = 7;

    int result = binarySearch(arr,0,n-1,key);

    (result==-1)
        ? cout << "Element is not found in the array" << endl
        : cout << "Element is found at index " << result;

    return 0;

}

Binary Search

10 101 61 126 217 2876 6127 39162 98126 712687 1000000000100 6127 1 61 200 -10000 1 217 10000 1000000000

Source: codeforces.com

Binary search

function binarySearchRicorsivo(array A, int p, int r, int v)
    if p > r
      return -1
     if v < A[p] or v > A[r]
       return -1
     q= (p+r)/2
     if A[q] == v
       return q
     else if A[q] > v
       return binarySearchRicorsivo(A,p,q-1,v)
     else

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