[문제] 가로수 2485번

https://www.acmicpc.net/problem/2485

public class StreeTree {

	public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
        int [] array = new int[n];
        int [] distance = new int[n];
        for(int i=0; i<n; i++){
        	array[i]= scan.nextInt();
        }
        for(int i=0; i<=n-2; i++){
        	distance[i]= array[i+1] - array[i];
        }
       for(int i=0; i<=n-2; i++){
    	   distance[i+1]= gcd(distance[i], distance[i+1]);
       }
       int interval = distance[n-2];
       int streetTree = ((array[n-1]-array[0])/interval)-(array.length-1);
       System.out.println(streetTree); // (마지막수 - 처음수 / interval) - existing tree 
	}

	private static int gcd(int a, int b) {
		if(b==0){
			return a;
		}
		else{
			return gcd(b, a%b);
		}
	}
}