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106 lines
2.3 KiB
106 lines
2.3 KiB
1 year ago
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fn cancel(n: u32, k: u8) -> u32 {
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let mut res = 0u32;
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let mut ds = Vec::new();
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let mut nn = n;
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while nn > 0 {
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let dd = nn % 10;
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if dd != k as u32 {
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ds.push(nn % 10);
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}
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nn /= 10;
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}
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for x in ds.iter().rev() {
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res *= 10;
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res += x;
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}
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return res;
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}
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fn gcd(mut a: u32, mut b: u32) -> u32 {
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while b != 0 {
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let remainder = a % b;
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a = b;
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b = remainder;
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}
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a
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}
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struct Fr {
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n: u32,
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d: u32
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}
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impl Fr {
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fn from(n: u32, d: u32) -> Fr {
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return Fr { n: n, d: d };
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}
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fn simple(&self) -> Fr {
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let g = gcd(self.n, self.d);
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let n = self.n / g;
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let d = self.d / g;
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return Fr { n: n, d: d };
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}
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fn print(&self) {
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println!("{}/{}", self.n, self.d);
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}
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fn eq(&self, other: &Fr) -> bool {
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let a = self.simple();
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let b = other.simple();
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return a.n == b.n && a.d == b.d;
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}
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fn ds(&self) -> Vec<u8> {
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let mut res = Vec::new();
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let mut n = self.n;
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let mut d = self.d;
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while n > 0 {
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res.push((n % 10) as u8);
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n /= 10;
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}
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while d > 0 {
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res.push((d % 10) as u8);
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d /= 10;
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}
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return res;
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}
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fn cancel(&self, k: u8) -> Fr {
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let n = cancel(self.n, k);
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let d = cancel(self.d, k);
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return Fr{ n: n, d: d };
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}
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fn can_cancel(&self, k: u8) -> bool {
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return cancel(self.n, k) != 0 && cancel(self.d, k) != 0;
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}
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fn test(&self) -> bool {
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let ds = self.ds();
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for k in ds {
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if !self.can_cancel(k) { continue; }
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let cn = self.cancel(k);
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if self.eq(&cn) {
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return true;
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}
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}
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return false;
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}
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}
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fn main() {
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let mut res_n = 1;
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let mut res_d = 1;
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for n in 10..99 {
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for d in n+1..99 {
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//println!("{}/{}", n, d);
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if n % 10 == 0 && d % 10 == 0 { continue; }
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let f = Fr::from(n, d);
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if f.test() {
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f.print();
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res_n *= n;
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res_d *= d;
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}
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}
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}
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let res_fr = Fr::from(res_n, res_d).simple();
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println!("{}", res_fr.d);
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}
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