Python: Search for an ordered list

Last update on April 02 2025 05:26:10 (UTC/GMT +8 hours)

3. Ordered Binary Search

Write a Python program for binary search of an ordered list.

Sample Solution:

Python Code:

def Ordered_binary_Search(olist, item):
    
    if len(olist) == 0:
        return False
    else:
        midpoint = len(olist) // 2
        if olist[midpoint] == item:
            return True
        else:
            if item < olist[midpoint]:
                return binarySearch(olist[:midpoint], item)
            else:
                return binarySearch(olist[midpoint+1:], item)

def binarySearch(alist, item):

    first = 0
    last = len(alist) - 1
    found = False

    while first <= last and not found:
        midpoint = (first + last) // 2
        if alist[midpoint] == item:
            found = True
        else:
            if item < alist[midpoint]:
                last = midpoint - 1
            else:
                first = midpoint + 1

    return found

print(Ordered_binary_Search([0, 1, 3, 8, 14, 18, 19, 34, 52], 3))
print(Ordered_binary_Search([0, 1, 3, 8, 14, 18, 19, 34, 52], 17))

Sample Output:

True                                                                                                          
False

Flowchart:

For more Practice: Solve these Related Problems:

• Write a Python program to perform binary search on an ordered list and return True if the target is found, otherwise False.
• Write a Python script to implement an iterative ordered binary search that logs each midpoint examined during the search.
• Write a Python function that uses binary search to verify the presence of a target in a sorted list and returns the number of steps required.
• Write a Python program that performs binary search on an ordered list of dates and outputs whether a given date exists in the list.

Python Code Editor:

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