[codeit] 이진탐색알고리즘 python

이진탐색알고리즘.py

def binary_search(element, some_list):
    answer = None

    startIdx=0
    endIdx=len(some_list) - 1


    if element < some_list[0] or element > some_list[len(some_list) - 1]:
        return None

    while answer == None:

        if some_list[startIdx] == element:
            answer = startIdx
            break
        elif some_list[endIdx] == element:
            answer = endIdx
            break

        middleIndex = int((endIdx + startIdx) / 2)
        if element > some_list[middleIndex]:
            startIdx =middleIndex + 1

            # search(some_list, middleIndex + 1, endIndex, targetValue)
        elif element < some_list[middleIndex]:
            endIdx =middleIndex-1
            # search(some_list, startIndex, middleIndex - 1, targetValue)
        else:
            return middleIndex

    return answer
    # 코드를 작성하세요.
    
    # print(binary_search(2, [2, 3, 5, 7, 11]))
# print(binary_search(0, [2, 3, 5, 7, 11]))
# print(binary_search(5, [2, 3, 5, 7, 11]))
print(binary_search(3, [2, 3, 5, 7, 11]))
# print(binary_search(11, [2, 3, 5, 7, 11]))