假币问题python代码

以下是两种假币问题的Python代码：

方法一：直接遍历所有纸币，找到质量小的纸币就返回下标，否则返回“找不到”

def findFalseCoin(coins, start, n):
    min = coins[start]
    flag = 0
    for i in range(start, n + 1):
        if coins[i] < min:
            flag = 1
            min = i
            break
        elif coins[i] > min:
            flag = 1
            min = start
            break
    if flag == 1:
        print("Fake coin:{}".format(min))
    else:
        print("Fake coin is not found")

coins = list(input().split(','))
coins = [int(i) for i in coins]
findFalseCoin(coins, 0, len(coins) - 1)

方法二：将两堆硬币上天平比较重量，如果有一堆较轻，那么假的硬币必然在轻的那一堆中。如果两堆硬币重量相等，且两堆之外有一个剩余硬币，则那个剩余硬币就是假硬币。如果两堆硬币重量相等，且两堆之外没有剩余硬币，则查找任务失败，未发现假硬币。

def findFalseCoin(coins):
    n = len(coins)
    if n % 2 == 0:
        left = coins[:n//2]
        right = coins[n//2:]
        left_sum = sum(left)
        right_sum = sum(right)
        if left_sum < right_sum:
            return findFalseCoin(left)
        elif left_sum > right_sum:
            return findFalseCoin(right)
        else:
            return -1
    else:
        left = coins[:n//2]
        right = coins[n//2+1:]
        left_sum = sum(left)
        right_sum = sum(right)
        if left_sum < right_sum:
            return findFalseCoin(left)
        elif left_sum > right_sum:
            return findFalseCoin(right)
        else:
            return coins[n//2]

coins = list(input().split(','))
coins = [int(i) for i in coins]
result = findFalseCoin(coins)
if result == -1:
    print("Fake coin is not found")
else:
    print("Fake coin:{}".format(result))