Codilityの勧め ~JavaScriptで解くアルゴリズム~の実践編です。
問題
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.
語彙メモ
-
located at position X位置Xにあります -
greater than or equal to YY以上 -
must perform to reach its target.ターゲットに到達するために実行しなければならない -
Write an efficient algorithm for the following assumptions:(:以下の)仮定のための効率的なアルゴリズムを書け
解法
必要知識
- parseInt()
- 三項演算子
太字にしているものは初見でした。
function solution(X, Y, D) {
// write your code in JavaScript (Node.js 8.9.4)
if (X >= Y) {
return 0;
} else if (D >= X + Y) {
return 1;
} else {
let minimalJumps = parseInt((Y - X) / D);
minimalJumps += (Y - X) % D > 0 ? 1 : 0;
return minimalJumps;
}
}
比較的簡単でした。
