## [leetCode] 1356. Sort Integers by The Number of 1 Bits (Python) 본문

Programming/코딩 1일 1문제

### [leetCode] 1356. Sort Integers by The Number of 1 Bits (Python)

사용자 솜씨좋은장씨 2020. 9. 16. 00:41

Given an integer array arr. You have to sort the integers in the array in ascending order by the number of 1's in their binary representation and in case of two or more integers have the same number of 1's you have to sort them in ascending order.

Return the sorted array.

Example 1:

``````Input: arr = [0,1,2,3,4,5,6,7,8]
Output: [0,1,2,4,8,3,5,6,7]
Explantion:  is the only integer with 0 bits.
[1,2,4,8] all have 1 bit.
[3,5,6] have 2 bits.
 has 3 bits.
The sorted array by bits is [0,1,2,4,8,3,5,6,7]``````

Example 2:

``````Input: arr = [1024,512,256,128,64,32,16,8,4,2,1]
Output: [1,2,4,8,16,32,64,128,256,512,1024]
Explantion: All integers have 1 bit in the binary representation, you should just sort them in ascending order.``````

Example 3:

``````Input: arr = [10000,10000]
Output: [10000,10000]``````

Example 4:

``````Input: arr = [2,3,5,7,11,13,17,19]
Output: [2,3,5,17,7,11,13,19]``````

Example 5:

``````Input: arr = [10,100,1000,10000]
Output: [10,100,10000,1000]``````

Constraints:

• 1 <= arr.length <= 500
• 0 <= arr[i] <= 10^4

Solution

``````class Solution:
def sortByBits(self, arr: List[int]) -> List[int]:
one_count_dict = {}
for i, num in enumerate(arr):
one_count = bin(num).count("1")

one_count_dict[i] = one_count

sorted_dict = sorted(one_count_dict.items(), key=lambda x:(x, arr[x]))

answer = [arr[num] for num in sorted_dict]