n-queens-ii

n-queens-ii/sol.rs

@@ -0,0 +1,29 @@
+// TODO : Tidy up?? This is quite the unreadable mess at the moment
+impl Solution {
+    pub fn search(board: Vec<Vec<i32>>) -> i32 {
+        if board.len() == 1 {
+            return board[0].len();
+        }
+        board[0].iter()
+            .map(|&current|
+                Solution::search(
+                    board[1..].iter()
+                        .enumerate()
+                        .map(|(idx, row)| {
+                            row.iter()
+                                .filter_map(|n| if *n != current &&
+                                    *n != current - idx as i32 - 1 &&
+                                    *n != current + idx as i32 + 1 {
+                                    Some(*n)
+                                } else { None })
+                                .collect()
+                        })
+                        .collect()
+                )
+            )
+            .sum()
+    }
+    pub fn total_n_queens(n: i32) -> Vec<Vec<String>> {
+        Solution::search(vec![(0..n).collect(); n as usize])
+    }
+}