【Codewars每日一题】- Find The Parity Outlier

题目

题目地址

You are given an array (which will have a length of at least 3, but could be very large) containing integers. The array is either entirely comprised of odd integers or entirely comprised of even integers except for a single integer N. Write a method that takes the array as an argument and returns this “outlier” N.

Examples

[2, 4, 0, 100, 4, 11, 2602, 36]
Should return: 11 (the only odd number)

[160, 3, 1719, 19, 11, 13, -21]
Should return: 160 (the only even number)

思路

最直接的思路就是遍历数组，前提要判断我们要找的目标是一个奇数还是偶数。根据数组中的前三个数字可以判断出目标数是奇还是偶。然后遍历数组，找到目标数。

答案

我的答案

def find_outlier(integers):
    if (isOddList(integers)):
        for i in integers:
            if not isOdd(i):
                return i
    else:
        for i in integers:
            if isOdd(i):
                return i

# 判断是否是奇数
def isOdd(num):
    if (num % 2) == 0:
        return False
    else:
        return True


# 判读是否是奇数数组，以前三个元素判断即可
def isOddList(integers):
    odd = 0
    even = 0
    for i in integers[0:3]:
        if (i % 2) == 0:
            even += 1
        else:
            odd += 1
    if odd > even:
        return True
    else:
        return False

最佳答案

def find_outlier(int):
    odds = [x for x in int if x%2!=0]
    evens= [x for x in int if x%2==0]
    return odds[0] if len(odds)<len(evens) else evens[0]

最佳答案的思路是分别将奇数和偶数筛选出为单独的list，然后比较最终的list大小可以得出目标数。该方法看着简洁明了。