1 files changed, 38 insertions, 0 deletions
diff --git a/lua/4.lua b/lua/4.lua
new file mode 100755
index 0000000..f965bc6
--- /dev/null
+++ b/lua/4.lua
@@ -0,0 +1,38 @@
+N = 8
+
+function isPlaceOK(a,n,c)
+    for i = 1, n - 1 do
+        if (a[i] == c) or
+            (a[i] - n == c - n) or
+            (a[i] + n == c + n) then
+            return false;
+        end
+    end
+    return true;
+end
+
+function printSolution(a)
+    for i = 1, N do
+        for j = 1, N do
+            io.write(a[i] == j and "X" or "-", ' ');
+        end
+        io.write('\n');
+    end
+    io.write('\n');
+end
+
+function addQueen(a, n)
+    if n > N    then
+        printSolution(a);
+    else
+        for c = 1, N do
+            if isPlaceOK(a,n,c) then
+                a[n] = c;
+                addQueen(a, n + 1);
+            end
+        end
+    end
+end
+
+
+addQueen({},1)