feat: completed solutions

exercises/18_iterators/iterators3.rs

@@ -11,21 +11,36 @@ enum DivisionError {
 // TODO: Calculate `a` divided by `b` if `a` is evenly divisible by `b`.
 // Otherwise, return a suitable error.
 fn divide(a: i64, b: i64) -> Result<i64, DivisionError> {
-    todo!();
+    match (a, b) {
+        (_, 0) => Err(DivisionError::DivideByZero),
+        (a, b) if a == i64::MIN && b == -1 => Err(DivisionError::IntegerOverflow),
+        (a, b) if a % b != 0 => Err(DivisionError::NotDivisible),
+        (a, b) => Ok(a / b),
+    }
 }
 
 // TODO: Add the correct return type and complete the function body.
 // Desired output: `Ok([1, 11, 1426, 3])`
-fn result_with_list() {
+fn result_with_list() -> Result<Vec<i64>, DivisionError> {
     let numbers = [27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let result: Vec<i64> = numbers
+        .into_iter()
+        .map(|n| divide(n, 27))
+        .collect::<Result<Vec<i64>, DivisionError>>()?;
+
+    Ok(result)
 }
 
 // TODO: Add the correct return type and complete the function body.
 // Desired output: `[Ok(1), Ok(11), Ok(1426), Ok(3)]`
-fn list_of_results() {
+fn list_of_results() -> Vec<Result<i64, DivisionError>> {
     let numbers = [27, 297, 38502, 81];
-    let division_results = numbers.into_iter().map(|n| divide(n, 27));
+    let division_results: Vec<Result<i64, DivisionError>> = numbers
+        .into_iter()
+        .map(|n| divide(n, 27))
+        .collect::<Vec<Result<i64, DivisionError>>>();
+
+    division_results
 }
 
 fn main() {