[c#] codility : frogjmp

<문제>

 

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

Write an efficient algorithm for the following assumptions:

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

 

Task Score : 100, Correctness 100, Performance 100%

 

 

<시간복잡도>

 

시간복잡도 : 상수시간 

 

<풀이>

public int Solution(int X, int Y, int D)
{
  var dis = Y - X;

  int count = dis / D;
  int remainder = dis % D;

  if (remainder == 0)
  	return count;
  else
  	return count + 1;
}