Assignment 5 solution

assignment5/.gitignore

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+target/

assignment5/Cargo.toml

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+[package]
+name = "assignment5"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+rand = "0.9.0"

assignment5/src/main.rs

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+use core::f32;
+use rand::{rngs::ThreadRng, Rng};
+use std::io;
+use std::time::Instant;
+
+fn main() {
+    let user_input: i32;
+    loop {
+        let mut guess = String::new();
+        println!("Please enter array size: ");
+
+        io::stdin()
+            .read_line(&mut guess)
+            .expect("failed to read line");
+
+        match guess.trim().parse() {
+            Ok(x) => {
+                if x < 1 || x > 100 {
+                    println!("number must be between 1 and 100");
+                    continue;
+                } else {
+                    user_input = x;
+                    break;
+                }
+            }
+            Err(error) => {
+                println!("error when parsing number: {error}");
+                continue;
+            }
+        };
+    }
+    println!("using input {user_input}");
+
+    let mut rand_nums: Vec<(f32, bool)> = Vec::new();
+    let mut rng = rand::rng();
+    for _ in 0..user_input {
+        rand_nums.push((rng.random_range(0.0..1.0), false));
+    }
+
+    const REPETITIONS: usize = 10;
+    let mut break_durations: [f32; REPETITIONS] = [0.0; REPETITIONS];
+    for i in 0..REPETITIONS {
+        let d = break_nums(&rand_nums, &mut rng);
+        println!("took {} seconds to guess everything", d);
+        break_durations[i] = d
+    }
+    let mut max = f32::NEG_INFINITY;
+    let mut min = f32::INFINITY;
+    let mut avg = 0.0;
+
+    for d in break_durations {
+        if d > max {
+            max = d;
+        }
+        if d < min {
+            min = d;
+        }
+        avg += d;
+    }
+    println!("min {}, max {}, avg {}", min, max, avg / REPETITIONS as f32);
+}
+
+fn break_nums(rand_nums: &Vec<(f32, bool)>, rng: &mut ThreadRng) -> f32 {
+    let now = Instant::now();
+
+    let mut rand_nums = rand_nums.clone();
+    let mut cnt = 0;
+    let size: i32 = rand_nums
+        .len()
+        .try_into()
+        .expect("size should be between 1 and 100");
+    loop {
+        let num: f32 = rng.random_range(0.0..1.0);
+        match rand_nums
+            .iter_mut()
+            .find(|(n, erased)| *n == num && !erased)
+        {
+            Some(found) => {
+                found.1 = true;
+                cnt += 1;
+                println!("erased {}", found.0);
+                if cnt == size {
+                    break;
+                }
+            }
+            None => {}
+        }
+    }
+
+    now.elapsed().as_secs_f32()
+}