给定一个数字列表，请编写一个函数，找出其中最大的两个不同数字，并且返回结果按照从大到小排列。
示例：
输入： [4, 10, 10, 9]，输出：[10, 9]
题目难度：简单
题目来源：codewars： Return Two Highest Values in List
def two_highest(nums: list) -> list:
pass
assert two_highest([4, 10, 10, 9]) == [10, 9]
assert two_highest([15, 20, 20, 17]) == [20, 17]
def two_highest(nums: list) -> list:
nums = list(set(nums))
nums.sort(reverse=True)
return nums[:2]
assert two_highest([4, 10, 10, 9]) == [10, 9]
assert two_highest([15, 20, 20, 17]) == [20, 17]
排序，切片［：2］
def two_highest(nums: list) -> list:
# 定义最大值变量，初始值为空
max_num = None
# 定义第二大值变量，初始值为空
second_num = None
# 遍历列表中的每个数字
for num in nums:
# 判断最大值变量为空，则进行赋值操作
# 或者该数字大于最大值，则进行赋值操作
if max_num is None or num > max_num:
max_num = num
# 判断该数字小于最大值，则进入第二次判断
if num < max_num:
# 判断第二大值变量为空，则进行赋值操作
# 或者该数字大于第二大值，则进行赋值操作
if second_num is None or num > second_num:
second_num = num
# 最大值或者第二大值为空，则剔除掉
# 然后返回列表
result = [v for v in [max_num, second_num] if v]
return result
assert two_highest([4, 10, 10, 9]) == [10, 9]
assert two_highest([15, 20, 20, 17]) == [20, 17]
assert two_highest([1, 1, 1]) == [1]
assert two_highest([]) == []
public List<Integer> twoHighest(List<Integer> arrayList) {
return arrayList.stream().sorted(Comparator.reverseOrder()).distinct().limit(2).collect(Collectors.toList());
}
@Test
public void testTwoHighest() {
twoHighest(Arrays.asList(4, 10, 10, 9)).stream().forEach(System.out::println);
twoHighest(Arrays.asList(15, 20, 20, 17)).stream().forEach(System.out::println);
}
第一种
def sort_list(list_num: List[int]) -> List[int]:
list_tmp = list(set(list_num))
list_tmp.sort(reverse=True)
return list_tmp[:2]
第二种
def sort_list(list_num: List[int]) -> List[int]:
set_dict = set(list_num)
list_tmp = list()
for num in set_dict:
if num in list_tmp: // 这个判断在使用set时，可以不写
continue
if not list_tmp:
list_tmp.append(num)
continue
for t in list_tmp:
if t < num:
list_tmp.insert(list_tmp.index(t), num)
break
return list_tmp[:2]
def two_highest(nums: list) -> list:
nums.sort(reverse=True)
two_highest_list = []
for n in nums:
if n not in two_highest_list:
two_highest_list.append(n)
if len(two_highest_list) == 2:
return two_highest_list
assert two_highest([4, 10, 10, 9]) == [10, 9]
assert two_highest([15, 20, 20, 17]) == [20, 17]
def two_highest(nums: list) -> list:
L = list(set(nums))
L.sort(reverse=True)
return L[:2]
assert two_highest([4, 10, 10, 9]) == [10, 9]
assert two_highest([15, 20, 20, 17]) == [20, 17]
def two_highest(nums: list) -> list:
nums = sorted(list(set(nums)))
nums.reverse()
return nums[:2]
assert two_highest([4, 10, 10, 9]) == [10, 9]
assert two_highest([15, 20, 20, 17]) == [20, 17]
Python参考题解：
import heapq
def two_highest(nums: list) -> list:
return heapq.nlargest(2, list(set(nums)))
assert two_highest([4, 10, 10, 9]) == [10, 9]
assert two_highest([15, 20, 20, 17]) == [20, 17]
思路：利用标准库heapq进行堆排序，获取最大的两个数。
def two_highest(nums: list) -> list:
set1 = set(nums)
list1 = list(set1)
list1.sort(reverse=True)
return list1[0:2]
assert two_highest([4, 10, 10, 9]) == [10, 9]
assert two_highest([15, 20, 20, 17]) == [20, 17]
def two_highest(nums: list) -> list:
return sorted(list(set(nums)), reverse=True)[:2]
assert two_highest([4, 10, 10, 9]) == [10, 9]
assert two_highest([15, 20, 20, 17]) == [20, 17]
def two_highest(nums: list) -> list:
return sorted(set(nums),reverse=True)[:2]
assert two_highest([4, 10, 10, 9]) == [10, 9]
assert two_highest([15, 20, 20, 17]) == [20, 17]