Ref: Move check outside to make it more sound

src/main.rs

@@ -67,16 +67,17 @@ fn main() {
 }
 
 fn parse_playfield(field: &String, field_size: usize) -> Playfield {
-    let playfield = &mut Playfield::new(field_size);
+    let mut playfield = Playfield::new(field_size);
 
     let chars = field.split(" ").collect::<Vec<&str>>();
 
-    if chars.len() != field_size * field_size {
+    if !is_right_field_size(&chars, field_size) {
         panic!(
             "Input must have dimension of size {size}x{size}",
             size = field_size
         );
     }
+
     for row in 0..field_size {
         for col in 0..field_size {
             let field = &mut playfield.fields[row][col];
@@ -86,11 +87,15 @@ fn parse_playfield(field: &String, field_size: usize) -> Playfield {
                 continue;
             }
 
-            field.value = Some(char_field.to_string().parse::<u32>().unwrap());
+            field.value = Some(char_field.parse().unwrap());
         }
     }
 
-    return playfield.clone();
+    return playfield;
+}
+
+fn is_right_field_size(field: &Vec<&str>, field_size: usize) -> bool {
+    return field.len() == field_size * field_size;
 }
 
 #[cfg(test)]