LeetCode-in-Java
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
import java.util.ArrayList;
import java.util.List;
@SuppressWarnings("java:S2234")
public class Solution {
public List<String> simplifiedFractions(int n) {
List<String> result = new ArrayList<>();
if (n == 1) {
return result;
}
StringBuilder str = new StringBuilder();
for (int denom = 2; denom <= n; denom++) {
for (int num = 1; num < denom; num++) {
if (checkGCD(num, denom) == 1) {
result.add(str.append(num).append("/").append(denom).toString());
}
str.setLength(0);
}
}
return result;
}
private int checkGCD(int a, int b) {
if (a < b) {
return checkGCD(b, a);
}
if (a == b || a % b == 0 || b == 1) {
return b;
}
return checkGCD(a % b, b);
}
}