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. The fractions can be 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".
Example 4:
Input: n = 1
Output: []
Constraints:
1 <= n <= 100
class Solution {
private int gcd(int x, int y) {
if (y == 0)
return x;
return gcd(y, x % y);
}
public List<String> simplifiedFractions(int n) {
List<String> ans = new ArrayList<>();
Set<String> set = new HashSet<>();
for (int i = 2; i <= n; i++) {
for (int j = 1; j < i; j++) {
int gcd = gcd(i, j);
int num = j / gcd, deno = i / gcd;
StringBuilder str = new StringBuilder();
str.append(Integer.toString(num) + "/" + Integer.toString(deno));
if (!set.contains(str.toString())) {
set.add(str.toString());
ans.add(str.toString());
}
}
}
return ans;
}
}