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| 1 | +use divan::black_box; |
| 2 | +use std::collections::{BTreeMap, HashMap}; |
| 3 | + |
| 4 | +fn main() { |
| 5 | + divan::main(); |
| 6 | +} |
| 7 | + |
| 8 | +#[divan::bench] |
| 9 | +fn add() -> i32 { |
| 10 | + black_box(2) + black_box(1) |
| 11 | +} |
| 12 | + |
| 13 | +#[divan::bench] |
| 14 | +#[ignore] |
| 15 | +fn sub() -> i32 { |
| 16 | + black_box(2) - black_box(1) |
| 17 | +} |
| 18 | + |
| 19 | +#[divan::bench] |
| 20 | +fn mul() -> i32 { |
| 21 | + black_box(2) * black_box(1) |
| 22 | +} |
| 23 | + |
| 24 | +#[divan::bench] |
| 25 | +fn div() -> i32 { |
| 26 | + black_box(2) / black_box(1) |
| 27 | +} |
| 28 | + |
| 29 | +#[divan::bench] |
| 30 | +fn rem() -> i32 { |
| 31 | + black_box(2) % black_box(1) |
| 32 | +} |
| 33 | + |
| 34 | +// 1, 1, 2, 3, 5, ... |
| 35 | +mod fibonacci { |
| 36 | + use super::*; |
| 37 | + |
| 38 | + const VALUES: &[u64] = &[0, 5, 10, 20, 30]; |
| 39 | + |
| 40 | + // O(n) |
| 41 | + #[divan::bench(args = VALUES)] |
| 42 | + fn iterative(n: u64) -> u64 { |
| 43 | + let mut previous = 1; |
| 44 | + let mut current = 1; |
| 45 | + |
| 46 | + for _ in 2..=n { |
| 47 | + let next = previous + current; |
| 48 | + previous = current; |
| 49 | + current = next; |
| 50 | + } |
| 51 | + |
| 52 | + current |
| 53 | + } |
| 54 | + |
| 55 | + // O(2^n) |
| 56 | + #[divan::bench(args = VALUES, max_time = 1)] |
| 57 | + fn recursive(n: u64) -> u64 { |
| 58 | + if n <= 1 { |
| 59 | + 1 |
| 60 | + } else { |
| 61 | + recursive(n - 2) + recursive(n - 1) |
| 62 | + } |
| 63 | + } |
| 64 | + |
| 65 | + #[allow(dead_code)] |
| 66 | + trait Map: Default { |
| 67 | + fn get(&self, key: u64) -> Option<u64>; |
| 68 | + fn set(&mut self, key: u64, value: u64); |
| 69 | + } |
| 70 | + |
| 71 | + impl Map for HashMap<u64, u64> { |
| 72 | + fn get(&self, key: u64) -> Option<u64> { |
| 73 | + self.get(&key).copied() |
| 74 | + } |
| 75 | + |
| 76 | + fn set(&mut self, key: u64, value: u64) { |
| 77 | + self.insert(key, value); |
| 78 | + } |
| 79 | + } |
| 80 | + |
| 81 | + impl Map for BTreeMap<u64, u64> { |
| 82 | + fn get(&self, key: u64) -> Option<u64> { |
| 83 | + self.get(&key).copied() |
| 84 | + } |
| 85 | + |
| 86 | + fn set(&mut self, key: u64, value: u64) { |
| 87 | + self.insert(key, value); |
| 88 | + } |
| 89 | + } |
| 90 | + |
| 91 | + // Will be ignored in instrumented mode as we do not support type generics yet |
| 92 | + // O(n) |
| 93 | + #[cfg(not(codspeed))] |
| 94 | + #[divan::bench( |
| 95 | + types = [BTreeMap<u64, u64>, HashMap<u64, u64>], |
| 96 | + args = VALUES, |
| 97 | + )] |
| 98 | + fn recursive_memoized<M: Map>(n: u64) -> u64 { |
| 99 | + fn fibonacci<M: Map>(n: u64, cache: &mut M) -> u64 { |
| 100 | + if let Some(result) = cache.get(n) { |
| 101 | + return result; |
| 102 | + } |
| 103 | + |
| 104 | + if n <= 1 { |
| 105 | + return 1; |
| 106 | + } |
| 107 | + |
| 108 | + let result = fibonacci(n - 2, cache) + fibonacci(n - 1, cache); |
| 109 | + cache.set(n, result); |
| 110 | + result |
| 111 | + } |
| 112 | + |
| 113 | + fibonacci(n, &mut M::default()) |
| 114 | + } |
| 115 | +} |
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