105 lines
2.0 KiB
Rust
105 lines
2.0 KiB
Rust
extern crate num_bigint_dig as num_bigint;
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extern crate num_integer;
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extern crate num_traits;
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mod biguint {
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use num_bigint::BigUint;
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use num_traits::Pow;
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use std::str::FromStr;
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fn check(x: u64, n: u32) {
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let big_x = BigUint::from(x);
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let res = big_x.nth_root(n);
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if n == 2 {
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assert_eq!(&res, &big_x.sqrt())
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} else if n == 3 {
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assert_eq!(&res, &big_x.cbrt())
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}
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assert!(res.pow(n) <= big_x);
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assert!((res + 1u32).pow(n) > big_x);
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}
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#[test]
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fn test_sqrt() {
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check(99, 2);
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check(100, 2);
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check(120, 2);
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}
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#[test]
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fn test_cbrt() {
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check(8, 3);
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check(26, 3);
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}
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#[test]
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fn test_nth_root() {
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check(0, 1);
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check(10, 1);
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check(100, 4);
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}
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#[test]
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#[should_panic]
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fn test_nth_root_n_is_zero() {
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check(4, 0);
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}
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#[test]
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fn test_nth_root_big() {
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let x = BigUint::from_str("123_456_789").unwrap();
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let expected = BigUint::from(6u32);
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assert_eq!(x.nth_root(10), expected);
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}
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}
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mod bigint {
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use num_bigint::BigInt;
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use num_traits::{Pow, Signed};
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fn check(x: i64, n: u32) {
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let big_x = BigInt::from(x);
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let res = big_x.nth_root(n);
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if n == 2 {
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assert_eq!(&res, &big_x.sqrt())
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} else if n == 3 {
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assert_eq!(&res, &big_x.cbrt())
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}
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if big_x.is_negative() {
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assert!(res.pow(n) >= big_x);
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assert!((res - 1u32).pow(n) < big_x);
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} else {
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assert!(res.pow(n) <= big_x);
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assert!((res + 1u32).pow(n) > big_x);
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}
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}
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#[test]
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fn test_nth_root() {
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check(-100, 3);
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}
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#[test]
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#[should_panic]
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fn test_nth_root_x_neg_n_even() {
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check(-100, 4);
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}
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#[test]
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#[should_panic]
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fn test_sqrt_x_neg() {
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check(-4, 2);
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}
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#[test]
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fn test_cbrt() {
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check(8, 3);
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check(-8, 3);
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}
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}
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