1 files changed, 58 insertions, 0 deletions
diff --git a/challenge-281/roger-bell-west/javascript/ch-2.js b/challenge-281/roger-bell-west/javascript/ch-2.js
new file mode 100755
index 0000000000..d14b70c0b6
--- /dev/null
+++ b/challenge-281/roger-bell-west/javascript/ch-2.js
@@ -0,0 +1,58 @@
+#! /usr/bin/node
+
+"use strict"
+
+function cs2xy(a) {
+    const x = a.charCodeAt(0) - 'a'.charCodeAt(0);
+    const y = a.charCodeAt(1) - '1'.charCodeAt(0);
+    return [x, y];
+}
+
+function knightsmove(from, to) {
+    const fc = cs2xy(from);
+    const tc = cs2xy(to);
+    let queue = [];
+    queue.push([fc[0], fc[1], 0]);
+    let seen = new Set;
+    while (queue.length > 0) {
+        const cc = queue.shift();
+        if (cc[0] == tc[0] && cc[1] == tc[1]) {
+            return cc[2];
+        } else {
+            for (let offset of [
+                [2, 1],
+                [1, 2],
+                [2, -1],
+                [1, -2],
+                [-2, 1],
+                [-1, 2],
+                [-2, -1],
+                [-1, -2]
+            ]) {
+                const x = cc[0] + offset[0];
+                const y = cc[1] + offset[1];
+                if (x >= 0 && x <= 7 && y >= 0 && y <= 7) {
+                    const cv = x * 8 + y;
+                    if (!seen.has(cv)) {
+                        queue.push([x, y, cc[2] + 1]);
+                        seen.add(cv);
+                    }
+                }
+            }
+        }
+    }
+    return -1;
+}
+
+if (knightsmove('g2', 'a8') == 4) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write(" ");
+if (knightsmove('g2', 'h2') == 3) {
+  process.stdout.write("Pass");
+} else {
+  process.stdout.write("FAIL");
+}
+process.stdout.write("\n");