improve manual agent code

src/agent.rs

@@ -16,22 +16,23 @@ impl Agent for ManualAgent {
     fn next_move(&mut self, _: &Board) -> Option<(usize, usize)> {
         let stdin = io::stdin();
         let mut input = String::new();
-        let mut got: Option<(usize, usize)> = None;
-        while got.is_none() {
+        loop {
             input.clear();
             stdin.lock().read_line(&mut input).ok()?;
-            let numbers = input
+
+            let got = input
                 .split_whitespace()
-                .map(|i| i.parse::<usize>().ok())
-                .collect::<Option<Vec<usize>>>();
-            if let Some(numbers) = numbers {
-                if numbers.len() == 2 {
-                    got = Some((numbers[0], numbers[1]));
+                .map(str::parse)
+                .map(Result::ok)
+                .collect::<Option<Vec<_>>>()
+                .and_then(|x| -> Option<[usize; 2]> { x.try_into().ok() })
+                .map(|x| (x[0], x[1]));
+
+            if got.is_some() {
+                return got;
             }
         }
     }
-        got
-    }
 
     fn name(&self) -> &'static str {
         "Manual Agent"