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Practice

Coding Quiz

This coding quiz is about implementing the binary search algorithm.

Write a program that checks whether a given value exists in a sorted list and returns the index of that value. If the value does not exist, the program should return -1.

Implementing Binary Search Algorithm
def solution(arr, target):
    return # Write your code here

Hint​

  • The binary search algorithm only works on a list that is sorted.

  • To find the middle value, you can use (left index + right index) // 2.

  • Choose the middle element of the list, and check if this middle value is the value you're looking for, or if it is smaller or larger. Then, reduce the search range by half and search again.

  • You can use loops or recursion.

Based on what you've learned so far, implement the binary search algorithm and check if it passes the test cases.

Click the model answer button at the bottom right to view an example of the function.



Input and Output Examples​

Example 1​

  • Input: [1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 7

  • Output: 6


Example 2​

  • Input: [1, 3, 5, 7, 9, 11, 13, 15], 4

  • Output: -1

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