Solution for Reversort Engineering

0327-Qualification/task3-reversort-engineering/Cargo.toml

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+[package]
+name = "task3-reversort-engineering"
+version = "0.1.0"
+authors = ["inga-lovinde <52715130+inga-lovinde@users.noreply.github.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

0327-Qualification/task3-reversort-engineering/src/main.rs

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+use std::{io::{self, BufRead}};
+
+fn create_list(len: usize, required_cost: usize, min_value: usize) -> Option<Vec<usize>> {
+    if len == 0 {
+        if required_cost == 0 {
+            return Some(Vec::new());
+        } else {
+            return None;
+        }
+    }
+
+    let potential_step_cost = len-1;
+    if potential_step_cost <= required_cost {
+        let mut result = create_list(len-1, required_cost - potential_step_cost, min_value + 1)?;
+        result.push(min_value);
+        result.reverse();
+        return Some(result);
+    } else {
+        let mut result = create_list(len-1, required_cost, min_value + 1)?;
+        result.push(min_value);
+        return Some(result);
+    }
+}
+
+fn solve(n: usize, c: usize) -> Option<Vec<usize>> {
+    if c + 1 < n {
+        return None;
+    }
+
+    let mut result = create_list(n, (c + 1) - n, 1)?;
+    result.reverse();
+    return Some(result);
+}
+
+fn main() {
+    let stdin = io::stdin();
+    let mut lines = stdin.lock().lines();
+
+    let test_number: u32 = lines.next().unwrap().unwrap().parse().unwrap();
+    for t in 1..=test_number {
+        let parts: Vec<usize> = lines.next().unwrap().unwrap().split(char::is_whitespace).map(|part| part.parse().unwrap()).collect();
+        let n = parts[0];
+        let c = parts[1];
+        println!("Case #{}: {}", t, match solve(n, c) {
+            Some(list) => list.iter().map(|n| n.to_string()).collect::<Vec<_>>().join(" "),
+            None => String::from("IMPOSSIBLE"),
+        });
+    }
+}