2分木探索

## ２分木探索 (Python)

# coding: utf-8

def binary_search(keyword, list1):
    # list1 に keyword に合致するものがあるかを 2分木探索で検索する

    # list1 をソートする
    list1.sort()

    # index を設定
    index_low = 0
    index_high = len(list1) - 1

    flag = 0
    while index_low <= index_high:
        index_mid = index_low + ((index_high - index_low) // 2)
        guess = list1[index_mid]
        if guess == keyword:
            flag = 1
            break
        elif guess > keyword:
            index_high = index_mid - 1
        elif guess < keyword:
            index_low = index_mid + 1

    if flag == 1:
        print("exist")
    else:
        print("not exist")


# 処理開始
list_a = [1, 5, 2, 4, 3]
keyword_a = 30

print(len(list_a))
binary_search(keyword_a, list_a)