1 files changed, 27 insertions, 0 deletions
diff --git a/tris/lines.go b/tris/lines.go
new file mode 100644
index 0000000..5cb6981
--- /dev/null
+++ b/tris/lines.go
@@ -0,0 +1,27 @@
+package tris
+
+func (f Field) Lines() (int, Field) {
+	full := [10]bool{true, true, true, true, true, true, true, true, true, true}
+	empty := [10]bool{false, false, false, false, false, false, false, false, false, false}
+	var n int
+	var nf [][10]bool
+
+	// count and collect
+	for _, line := range f {
+		if line == full {
+			n++
+		} else {
+			nf = append(nf, line)
+		}
+	}
+
+	// compress
+	for i := 0; i < 20; i++ {
+		if i < n {
+			f[i] = empty
+		} else {
+			f[i] = nf[i-n]
+		}
+	}
+	return n, f
+}