task04.java

/*	FrogJmp
	Count minimal number of jumps from position X to Y.
	Task Score 100%, Correctness 100%, Performance 100%
	
	A small frog wants to get to the other side of the road. The frog is currently located at position X and wants to get to a position greater than or equal to Y. The small frog always jumps a fixed distance, D.

	Count the minimal number of jumps that the small frog must perform to reach its target.

	Write a function:

	class Solution { public int solution(int X, int Y, int D); }

	that, given three integers X, Y and D, returns the minimal number of jumps from position X to a position equal to or greater than Y.

	For example, given:

	  X = 10
	  Y = 85
	  D = 30
	the function should return 3, because the frog will be positioned as follows:

	after the first jump, at position 10 + 30 = 40
	after the second jump, at position 10 + 30 + 30 = 70
	after the third jump, at position 10 + 30 + 30 + 30 = 100
	Assume that:

	X, Y and D are integers within the range [1..1,000,000,000];
	X ≤ Y.
	Complexity:

	expected worst-case time complexity is O(1);
	expected worst-case space complexity is O(1)	*/	
	
class Solution {
    public int solution(int X, int Y, int D) {
        return (int)Math.ceil((Y - X) / (double)D);
    }
}