Binary Search Java / Python

Binary Search using Python Bisect and Java Arrays.binarySearch()¶

Source Material¶

https://docs.python.org/2/library/bisect.html

https://www.geeksforgeeks.org/arrays-binarysearch-java-examples-set-1/

In [1]:

import bisect

def binSearch(a, x):
     # Return leftmost index of x
     # If not found, return (negative proper index-1)
    i = bisect.bisect_left(a, x)
    if i!=len(a) and a[i] == x:
        return i
    else:
        return -1*i-1

arr = [8,6,4,2]
arr.sort()

print(arr)
for i in range(11):
    print("  ",i," found at index = ",binSearch(arr,i))

[2, 4, 6, 8]
   0  found at index =  -1
   1  found at index =  -1
   2  found at index =  0
   3  found at index =  -2
   4  found at index =  1
   5  found at index =  -3
   6  found at index =  2
   7  found at index =  -4
   8  found at index =  3
   9  found at index =  -5
   10  found at index =  -5

---

import java.util.Arrays;

public class bsdemo {
    public static void main(String[] args)
    {
        int arr[] = {8,6,4,2};

        Arrays.sort(arr);
        System.out.println(Arrays.toString(arr));

        for(int i=0; i<11;i++) {

            System.out.println("  " + i + " found at index = "
                               +Arrays.binarySearch(arr,i));
        }
    }
}

---

[2, 4, 6, 8]
  0 found at index = -1
  1 found at index = -1
  2 found at index = 0
  3 found at index = -2
  4 found at index = 1
  5 found at index = -3
  6 found at index = 2
  7 found at index = -4
  8 found at index = 3
  9 found at index = -5
  10 found at index = -5