Fix VCF bug (#120)

* cargo update

* add test

* fix warning

* fix bug arround finding forced move when the last move is none

src/board/line.rs

@@ -135,7 +135,7 @@ impl FromStr for Line {
         }
         let mut line = Self::new(size as u8);
         for (i, c) in chars.into_iter().enumerate() {
-            Player::try_from(c).map_or((), |p| line.put_mut(p, i as u8));
+            let _ = Player::try_from(c).map_or((), |p| line.put_mut(p, i as u8));
         }
         Ok(line)
     }

src/mate/game.rs

@@ -129,7 +129,11 @@ impl Game {
                 .flat_map(|r| r.eyes());
             Self::take_distinct_two(last_four_eyes)
         } else {
-            (None, None)
+            let four_eyes = self
+                .board
+                .structures(self.turn.opponent(), Four)
+                .flat_map(|r| r.eyes());
+            Self::take_distinct_two(four_eyes)
         }
     }
 

src/mate/solve.rs

@@ -106,9 +106,6 @@ fn validate(board: &Board, attacker: Player) -> Result<(), Option<Mate>> {
     if board.structures(Black, OverFive).next().is_some() {
         return Err(None);
     }
-    if board.structures(attacker.opponent(), Four).next().is_some() {
-        return Err(None);
-    }
     if board.structures(attacker, Four).next().is_some() {
         return Err(Some(Mate::new(Unknown, vec![])));
     }
@@ -260,6 +257,35 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn test_vcf_counter() -> Result<(), String> {
+        let board = "
+        . . . . . . . . . . . . . . .
+        . . . . . . . . . . . . . . .
+         . . . . . . . . . . . . . . .
+         . . . . . . . . . . . . . . .
+         . . . . . . . . . . . . . . .
+         . . . . . . . . . . . . . . .
+         . . . . . . . x . . . . . . .
+         . . . . . . . o . o o x . . .
+         . . . . . . . . o x . o . . .
+         . . . . . . . . o . x . . . .
+         . . . . . . . . x . . x . . .
+         . . . . . . . . . . . . . . .
+         . . . . . . . . . . . . . . .
+         . . . . . . . . . . . . . . .
+         . . . . . . . . . . . . . . .
+        "
+        .parse::<Board>()?;
+
+        let solution: String = "I8,G8,I10,I9,J9".split_whitespace().collect();
+
+        let result = solve(VCFDFS, u8::MAX, &board, Black, 0);
+        assert_eq!(path_string(result), solution);
+
+        Ok(())
+    }
+
     #[test]
     fn test_vct_black() -> Result<(), String> {
         // No. 02 from 5-moves-to-end problems by Hiroshi Okabe