领扣-哈希表练习

136.只出现一次的数字

# -*- coding: utf-8 -*-
import collections
def singleNumber(nums):
    """
    :type nums: List[int]
    :rtype: int
    """
    s = []
    for i in nums:
        if i not in s:
            s.append(i)
        elif i in s:
            s.remove(i)
    return s[0]

def singleNumber2(nums):
    s = {}
    for i in nums:#i是列表中的每个元素
        if i in s.keys(): #在s的键中
            s.pop(i) #根据键删除值
        else:
            s[i] = 1 #{1：1，2：1，4：1}
    print(s.keys())
    return list(s.keys())[0] #无[0]的话为列表
#思路是运用按位异或运算符，当两对应的二进位相异结果为1
def singleNumber3(nums):
    """
    :type nums: List[int]
    :rtype: int
    """
    res = 0
    for i in nums:
        res^=i
    return res
#4：100^000=100(4)
#1: 100^001=101(5)
#2: 101^010=111(7)
#1: 111^001=110(6)
#2: 110^010=100(4)
def singleNumber4(nums):
    """
    :type nums: List[int]
    :rtype: int
    """
    x= [i for i in nums if nums.count(i) == 1]
    return x[0]
def singleNumber5(nums):
    """
    :type nums: List[int]
    :rtype: int
    """
    x = collections.Counter(nums)
    #for key,value in x.items():
    for key, value in x.items():
        if value < 2:
            return key

def singleNumber6( nums):
    """
    :type nums: List[int]
    :rtype: int
    """
    while len(nums) != 1:
        lastCha = nums.pop() #2、弹出最后一个元素
        if lastCha in nums:
            nums.remove(lastCha)
        else:
            return lastCha
    return nums[0]

def singleNumber7(nums):
    """
    :type nums: List[int]
    :rtype: int
    """
    nums.sort()#从小到大排序
    for i in range(0, len(nums) - 1, 2):
        if nums[i] != nums[i + 1]:
            return nums[i]
    return nums[-1]


if __name__ == '__main__':
    print(singleNumber([4,1,2,1,2]))
    print(singleNumber2([4, 1, 2, 1, 2]))
    print(singleNumber3([4, 1, 2, 1, 2]))
    print(singleNumber7([4, 1, 2, 1, 2]))

202快乐数

# -*- coding: utf-8 -*-

class Solution:
    def isHappy1(self, n):#方法一：一直调用isHappy函数，try...except Exception as e,超出时间限制
        try:
            if n == 1:
                return True
            else:
                new = str(n)
                sum = 0
                for c in new:
                    sum += int(c) ** 2
                return self.isHappy1(sum)
        except Exception as e:
            return False
#思路
class Solution2:
    def isHappy(self, n):
        temp = []
        while True:
            n = self.get_add(n)
            if n == 1:
                return True
            elif n in temp:
                return False
            else:
                temp.append(n)

    def get_add(self, n):
        ret = 0
        while n != 0:
            g = n % 10
            ret += g ** 2
            n = int(n / 10)
        return ret
class Solution3(object):
    def isHappy(self, n):
        """
        :type n: int
        :rtype: bool
        """
        d = []
        while True:
            l1=list(str(n))
            l2=list(l1)
            l3=map(int,l1)
            l = list(map(int,list(str(n))))
            m = 0
            for i in l:
                m += i**2
            if m in d:
                print(d)
                return False
            if m == 1:
                print(d)
                return True
            #d[m] = m
            d.append(m)
            n = m
#print(happy(36))
u=Solution3()
print(u.isHappy(19))