LeetCode in Kotlin
1447. Simplified Fractions
Medium
Given an integer n, return a list of all simplified fractions between 0 and 1 (exclusive) such that the denominator is less-than-or-equal-to n. You can return the answer in any order.
Example 1:
Input: n = 2
Output: [“1/2”]
Explanation: “1/2” is the only unique fraction with a denominator less-than-or-equal-to 2.
Example 2:
Input: n = 3
Output: [“1/2”,”1/3”,”2/3”]
Example 3:
Input: n = 4
Output: [“1/2”,”1/3”,”1/4”,”2/3”,”3/4”]
Explanation: “2/4” is not a simplified fraction because it can be simplified to “1/2”.
Constraints:
1 <= n <= 100
Solution
class Solution {
fun simplifiedFractions(n: Int): List<String> {
val result: MutableList<String> = ArrayList()
if (n == 1) {
return result
}
val str = StringBuilder()
for (denom in 2..n) {
for (num in 1 until denom) {
if (checkGCD(num, denom) == 1) {
result.add(str.append(num).append("/").append(denom).toString())
}
str.setLength(0)
}
}
return result
}
private fun checkGCD(a: Int, b: Int): Int {
if (a < b) {
return checkGCD(b, a)
}
return if (a == b || a % b == 0 || b == 1) {
b
} else checkGCD(a % b, b)
}
}