[알고리즘/Java] 코딜리티(Codility) Lesson 3-1 FrogJmp

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.

 

 

 

 

 

Solution)

// you can also use imports, for example:

// import java.util.*;

 

// you can write to stdout for debugging purposes, e.g.

// System.out.println("this is a debug message");

 

class Solution {

    public int solution(int X, int Y, int D) {

        // write your code in Java SE 8

        return ((Y-X) / D) + ((Y-X) % D == 0 ? 0 : 1);

    }

}