3475: Yaroslav and Permutations
Description
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.
The first line contains integer n (1≤n≤100) − the number of elements in the array. The second line contains n integers a1,a2,...,an (1≤ai≤1000) − the array elements.
In the single line print "YES" (without the quotes) if Yaroslav can obtain the array he needs, and "NO" (without the quotes) otherwise.
1
1
YES
3
1 1 2
YES
4
7 7 7 7
NO
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.