codeforces easy round problem C1 - Nice Array Solution

codeforces easy round problem C1 - Nice Array : http://codeforces.com/gym/200470/problem/C1

C1. Nice array

time limit per test

2 seconds

memory limit per test

64 megabytes

input

standard input

output

standard output

Let’s call an array ‘nice’ if the result of some permutation of it, you can get a series of numbers that form an arithmetic progression. I want to know whether the specified array is nice.

Input

The first line of the input file contains a natural n (2 <  = n <  = 100) The second string contains n integers ( - 1000 <  = ai <  = 1000)

Output

In a single line of output file output "YES" or "NO" (without the quotes) - depending on whether the array of nice

Sample test(s)

input

3
2 3 1

output

YES

input

3
2 3 2

output

NO

Note

In the first test array can be written as a sequence of 1 2 3 - arithmetic progression with difference 1, the second is impossible.

codeforces easy round problem C1 - Nice Array Solution :  http://codeforces.com/gym/200470/submission/6100552

#include <iostream>
#include <cstdio>
#include <cstdlib>
using namespace std;

int cmp(const void *a, const void *b) {
    return (*(int *)a - *(int *)b);}

int main() {
    int a, b[2005], cnt, c;
    scanf("%d", &a);
    cnt=0; 
    for(int i=0; i<a; i++) scanf("%d", &b[i]);
    qsort(b, a, sizeof(int), cmp);
    c=b[1]-b[0];
    for(int i=1; i<a; i++) {
        if(b[i]-b[i-1]==c) cnt++;
    }
    if(cnt+1==a) printf("YES");
    else printf("NO");
    return 0;
}