Create 51-n-queens.js

Author: everthis

51-n-queens.js

@@ -0,0 +1,27 @@
+/**
+ * @param {number} n
+ * @return {string[][]}
+ */
+const solveNQueens = function(n) {
+  const res = []
+  bt(res, n)
+  return res
+}
+
+function bt(res, n, board = [], r = 0) {
+  if (r === n) {
+    res.push(board.map(c => '.'.repeat(c) + 'Q' + '.'.repeat(n - c - 1)))
+    return
+  }
+  for (let c = 0; c < n; c++) {
+    if (
+      !board.some(
+        (bc, br) => bc === c || bc === c + r - br || bc === c - r + br
+      )
+    ) {
+      board.push(c)
+      bt(res, n, board, r + 1)
+      board.pop()
+    }
+  }
+}