-
Notifications
You must be signed in to change notification settings - Fork 0
/
canReorderDoubled.py
57 lines (42 loc) · 1.2 KB
/
canReorderDoubled.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
# https://leetcode.com/problems/array-of-doubled-pairs/description/
# 954. Array of Doubled Pairs
# Given an array of integers A with even length, return true if and only if it is possible to reorder it such that A[2 * i + 1] = 2 * A[2 * i]
# for every 0 <= i < len(A) / 2.
# Example 1:
# Input: [3,1,3,6]
# Output: false
# Example 2:
# Input: [2,1,2,6]
# Output: false
# Example 3:
# Input: [4,-2,2,-4]
# Output: true
# Explanation: We can take two groups, [-2,-4] and [2,4] to form [-2,-4,2,4] or [2,4,-2,-4].
# Example 4:
# Input: [1,2,4,16,8,4]
# Output: false
# Note:
# 0 <= A.length <= 30000
# A.length is even
# -100000 <= A[i] <= 100000
from collections import Counter as c
def canReorderDoubled(A):
"""
:type A: List[int]
:rtype: bool
"""
d = c(A)
for num in sorted(A, key=abs):
if d[num] == 0:
continue
if d[num * 2] == 0:
return False
d[num] -= 1
d[num * 2] -= 1
return True
assert canReorderDoubled([4, -2, -4, 8, -16, -32]) == True
assert canReorderDoubled([1, 2, 4, 8]) == True
assert canReorderDoubled([3, 1, 3, 6]) == False
assert canReorderDoubled([2, 1, 2, 6]) == False
assert canReorderDoubled([4, -2, 2, -4]) == True
assert canReorderDoubled([1, 2, 4, 16, 8, 4]) == False