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use std::collections::HashMap;
pub fn cosine_similarity(u: HashMap<u32, f32>, v: HashMap<u32, f32>) -> f32 {
let mut dot_prod: f32 = 0f32;
let mut u_norm: f32 = 0f32;
let mut v_norm: f32 = 0f32;
for (key, u_element) in &u {
let v_element = match &v.get(&key){
Some(element) => element,
None => &0f32,
};
dot_prod = dot_prod + (u_element * v_element);
u_norm = u_norm + u_element;
}
for (_, v_element) in &v{
v_norm = v_norm + v_element;
}
let similarity:f32 = dot_prod/(u_norm * v_norm);
similarity
}