题解 | #牛牛的冒险旅程#

#coding:utf-8
class ListNode:
    def __init__(self, x):
        self.val = x
        self.next = None
#
# 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
#
# 
# @param head ListNode类 
# @return int整型
#
def gcd(a, b):
    while b:
        a, b = b, a % b
    return a
class Solution:
    
    def gcdInCycle(self , head ):
        # write code here
        cur = head
        len = 0
        count={}
        list1,list2,list3 =[],[],[]
        while cur:
            list1.append(cur.val)
            cur = cur.next
            len+=1
        cur=head
        
        for num in list1:
            if num in count:
                count[num]+=1
            else:
                count[num]=1
        print(count)
        for key,value in count.items():
            if value!=1:
                list2.append(key)
            else:
                list3.append(1)
        if sum(list3)==len:
            return -1
        else:
            gcd_result = list2[0]
            for num in list2[1:]:
                gcd_result = gcd(gcd_result, num)
            return gcd_result