#K64172. Zigzag Breaths Pattern
Zigzag Breaths Pattern
Zigzag Breaths Pattern
You are given a sequence of integers representing the number of breaths. The task is to determine whether it is possible to reorder these integers into a zigzag pattern.
A sequence a0, a1, a2, ... , an-1 is said to be in a zigzag pattern if it satisfies:
\(a_0 a_2 a_4 < \cdots\)
Your task is to check if such a reordering of the given sequence exists. If it is possible, print YES
; otherwise, print NO
.
Note: For sequences of length 1 or 2, the answer is always YES
since they trivially satisfy the zigzag condition.
inputFormat
The input is read from standard input.
The first line contains an integer n
(1 ≤ n ≤ 105), the number of elements in the sequence. The second line contains n
space-separated integers representing the breaths.
outputFormat
Output a single line containing YES
if the sequence can be reordered to form a zigzag pattern, or NO
otherwise.
7
4 3 7 8 6 2 1
YES