add new solutions

solutions/14/q1411/solution.go

@@ -0,0 +1,62 @@
+package q1411
+
+type Color uint8
+
+const MODULO int = 1e9 + 7
+
+func numOfWays(n int) int {
+	patterns := make([][3]Color, 0, 12)
+	for a := range 3 {
+		for b := range 3 {
+			for c := range 3 {
+				if a == b || b == c {
+					continue
+				}
+				patterns = append(patterns, [3]Color{Color(a), Color(b), Color(c)})
+			}
+		}
+	}
+
+	// Find compatible patterns
+	compatiblePtns := make([][]int, len(patterns))
+	for i := range len(patterns) - 1 {
+		for j := i + 1; j < len(patterns); j++ {
+			ok := true
+			for k := range 3 {
+				if patterns[i][k] == patterns[j][k] {
+					ok = false
+					break
+				}
+			}
+			if ok {
+				compatiblePtns[i] = append(compatiblePtns[i], j)
+				compatiblePtns[j] = append(compatiblePtns[j], i)
+			}
+		}
+	}
+
+	counts := make([]int, len(patterns))
+	for i := range counts {
+		counts[i] = 1
+	}
+
+	countsNext := make([]int, len(patterns))
+	for range n - 1 {
+		for i := range len(patterns) {
+			countsNext[i] = 0
+			for _, j := range compatiblePtns[i] {
+				countsNext[i] += counts[j]
+			}
+			countsNext[i] %= MODULO
+		}
+		counts, countsNext = countsNext, counts
+	}
+
+	sum := 0
+	for _, c := range counts {
+		sum += c
+	}
+	return sum % MODULO
+}
+
+var _ = numOfWays