A9059. Yaroslav and Permutations
编程题
普及/提高-
知识点
题目描述
Yaroslav has an array that consists of $n$ integers. In one second Yaroslav can swap two neighboring array elements. Now Yaroslav is wondering if he can obtain an array where any two neighboring elements would be distinct in a finite time.
Help Yaroslav.
Help Yaroslav.
输入格式
The first line contains integer $n$ $(1<=n<=100)$ — the number of elements in the array. The second line contains $n$ integers $a_{1},a_{2},...,a_{n}$ $(1<=a_{i}<=1000)$ — the array elements.
输出格式
In the single line print "YES" (without the quotes) if Yaroslav can obtain the array he needs, and "NO" (without the quotes) otherwise.
输入输出样例
输入 #1
1 1
输出 #1
YES
输入 #2
3 1 1 2
输出 #2
YES
输入 #3
4 7 7 7 7
输出 #3
NO
说明/提示
In the first sample the initial array fits well.
In the second sample Yaroslav can get array: $1$ , $2$ , $1$ . He can swap the last and the second last elements to obtain it.
In the third sample Yarosav can't get the array he needs.
In the second sample Yaroslav can get array: $1$ , $2$ , $1$ . He can swap the last and the second last elements to obtain it.
In the third sample Yarosav can't get the array he needs.