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:
function solution(X, Y, 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.
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설명
X : 시작 위치 Y : 도착 위치 D : 증가량
X+nD > Y의 n을 구하기 도착위치에서 시작위치를 뺀 후 증가량 D로 나누기 다른 언어의 경우 기본적으로 정수형 연산이기 때문에 나머지가 있으면 몫+1 이지만 javascript는 기본적으로 모든 숫자의 연산이 정수가 아닌 실수형이기 때문에 올림으로 계산하면 됨
코드
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functionsolution(X, Y, D) { // write your code in JavaScript (Node.js 8.9.4) returnMath.ceil((Y - X) / D); }
