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use std::collections::HashMap;
use codspeed::{codspeed::black_box, codspeed_bench, codspeed_main};
pub fn fibonacci_recursive_cached(n: u64) -> u64 {
fn inner(n: u64, cache: &mut HashMap<u64, u64>) -> u64 {
match n {
0 | 1 => 1,
_ => {
if cache.contains_key(&n) {
*cache.get(&n).unwrap()
} else {
let result = inner(n - 1, cache) + inner(n - 2, cache);
cache.insert(n, result);
result
}
}
}
}
let mut cache = HashMap::new();
inner(n, &mut cache)
}
pub fn fibonacci_recursive(n: i32) -> u64 {
match n {
0 | 1 => 1,
_ => fibonacci_recursive(n - 1) + fibonacci_recursive(n - 2),
}
}
pub fn fibonacci_iterative(n: u64) -> u64 {
if n <= 1 {
return n;
}
let mut sum = 0;
let mut last = 0;
let mut curr = 1;
for _i in 1..n {
sum = last + curr;
last = curr;
curr = sum;
}
sum
}
codspeed_bench!(fibo_recursive, || fibonacci_recursive(black_box(10)));
codspeed_bench!(fibo_iterative, || fibonacci_iterative(black_box(10)));
codspeed_bench!(fibo_recursive_cached, || fibonacci_recursive_cached(
black_box(10)
));
codspeed_main!(fibo_recursive, fibo_iterative, fibo_recursive_cached);
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