number_utils/
number_utils.rs

1use crate::impl_number_utils_for;
2use std::marker::Sized;
3
4impl_number_utils_for!(u32, u64, u128, usize);
5
6pub trait NumberUtils {
7    /// Calculates factorial.
8    ///
9    /// # Examples
10    /// Basic usage:
11    /// ```
12    /// # use number_utils::NumberUtils;
13    /// # fn main() {
14    /// let n: u32 = 6;
15    /// assert_eq!(n.factorial(), 720);
16    /// # }
17    /// ```
18    fn factorial(&self) -> Self;
19
20    /// Calculates k-permutations.
21    ///
22    /// # Examples
23    /// Basic usage:
24    /// ```
25    /// # use number_utils::NumberUtils;
26    /// # fn main() {
27    /// let n: u32 = 6;
28    /// assert_eq!(n.permutation(3), 120);
29    /// # }
30    /// ```
31    fn permutation(&self, k: u32) -> Self;
32
33    /// Calculates k-combination.
34    ///
35    /// # Examples
36    /// Basic usage:
37    /// ```
38    /// # use number_utils::NumberUtils;
39    /// # fn main() {
40    /// let n: u32 = 6;
41    /// assert_eq!(n.combination(3), 20);
42    /// # }
43    /// ```
44    fn combination(&self, k: u32) -> Self;
45
46    /// Calculates greatest common divisor of two integers.
47    ///
48    /// # Examples
49    /// Basic usage:
50    /// ```
51    /// # use number_utils::NumberUtils;
52    /// # fn main() {
53    /// let n: u32 = 54;
54    /// assert_eq!(n.gcd(24), 6);
55    /// # }
56    /// ```
57    fn gcd(&self, m: Self) -> Self;
58
59    /// Calculates least common multiple.
60    ///
61    /// # Examples
62    /// Basic usage:
63    /// ```
64    /// # use number_utils::NumberUtils;
65    /// # fn main() {
66    /// let n: u32 = 72;
67    /// assert_eq!(n.lcm(10), 360);
68    /// # }
69    fn lcm(&self, m: Self) -> Self;
70
71    /// Calculates integer square root.
72    ///
73    /// # Examples
74    /// Basic usage:
75    /// ```
76    /// # use number_utils::NumberUtils;
77    /// # fn main() {
78    /// let n: u32 = 122;
79    /// assert_eq!(n.isqrt(), 11);
80    /// # }
81    /// ```
82    fn isqrt(&self) -> Self;
83
84    /// Calculates factorial, returning None if overflow occured.
85    ///
86    /// # Examples
87    /// Basic usage:
88    /// ```
89    /// # use number_utils::NumberUtils;
90    /// # fn main() {
91    /// let n: u32 = 5;
92    /// assert_eq!(n.checked_factorial(), Some(120));
93    /// assert_eq!(u32::MAX.checked_factorial(), None);
94    /// # }
95    /// ```
96    fn checked_factorial(&self) -> Option<Self>
97    where
98        Self: Sized;
99
100    /// Calculates k-permutations, returning None if overflow occured.
101    ///
102    /// # Examples
103    /// Basic usage:
104    /// ```
105    /// # use number_utils::NumberUtils;
106    /// # fn main() {
107    /// let n: u32 = 6;
108    /// assert_eq!(n.checked_permutation(3), Some(120));
109    /// assert_eq!(u32::MAX.checked_permutation(3), None);
110    /// # }
111    /// ```
112    fn checked_permutation(&self, k: u32) -> Option<Self>
113    where
114        Self: Sized;
115
116    /// Calculates k-combination, returning None if overflow occured.
117    ///
118    /// # Examples
119    /// Basic usage:
120    /// ```
121    /// # use number_utils::NumberUtils;
122    /// # fn main() {
123    /// let n: u32 = 6;
124    /// assert_eq!(n.checked_combination(3), Some(20));
125    /// assert_eq!(u32::MAX.checked_combination(1200), None);
126    /// # }
127    /// ```
128    fn checked_combination(&self, k: u32) -> Option<Self>
129    where
130        Self: Sized;
131
132    /// Calculates number of digits.
133    ///
134    /// # Examples
135    /// ```
136    /// # use number_utils::NumberUtils;
137    /// # fn main() {
138    /// let n: u32 = 1234567890;
139    /// assert_eq!(n.digits(), 10);
140    /// # }
141    /// ```
142    fn digits(&self) -> Self;
143}
144
145/// Implementation of the Pascal's triangle.
146///
147/// # Examples
148/// ```
149/// # use number_utils::pascals_triangle;
150/// # fn main() {
151/// assert_eq!(pascals_triangle(3), vec![1, 1, 1, 1, 2, 1]);
152/// # }
153/// ```
154pub fn pascals_triangle(n: usize) -> Vec<usize> {
155    let mut result = vec![1];
156    for i in 1..n {
157        let r = result.len() - i;
158        result.push(1);
159        for j in 1..i {
160            result.push(result[r + j - 1] + result[r + j]);
161        }
162        result.push(1);
163    }
164    result
165}
number_utils/number_utils.rs

number_utils/
number_utils.rs
