【leetcode】461. Hamming Distance

用了很多笨方法的感觉

class Solution(object):
    def hammingDistance(self, x, y):
        """
        :type x: int
        :type y: int
        :rtype: int
        """
        xlist = []
        ylist = []
        while(True):
            xlist.append(x%2)
            x/=2
            if x==0:
                break
        while(True):
            ylist.append(y%2)
            y/=2
            if y==0:
                break
        cnt = 0
        if len(ylist)>len(xlist):
            lenth = len(xlist)
            cntt = ylist[lenth:].count(0)
        else:
            lenth = len(ylist)
            cntt = xlist[lenth:].count(0)
        for i in range(lenth):
            if ylist[i]!=xlist[i]:
                cnt += 1
        return cnt+abs(len(ylist)-len(xlist))-cntt

38ms  38.43%

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果然看discuss喷出一口老血

class Solution(object):
    def hammingDistance(self, x, y):
        """
        :type x: int
        :type y: int
        :rtype: int
        """
        return bin(x^y).count('1')

33ms 95.17%

学习bin()函数。返回int类型的二进制表示法，返回类型为string，骚气的是注意前面有'0b'

比如bin(10)为‘0b1010’

比如bin(10).count('b') 为1

---------------------------------

class Solution(object):
    def hammingDistance(self, x, y):
        """
        :type x: int
        :type y: int
        :rtype: int
        """
        x = x ^ y
        y = 0
        while x:
            y += 1
            x = x & (x - 1)
        return y

33ms    95.17% （这个号称beat 100%，可能在他那个时候吧。。）