add new solutions

solutions/0/q48/solution.go

@@ -0,0 +1,21 @@
+package q48
+
+func rotateCell(matrix [][]int, x, y int) {
+	t := matrix[y][x]
+	for range 4 {
+		nextX, nextY := len(matrix)-1-y, x
+		matrix[nextY][nextX], t = t, matrix[nextY][nextX]
+		x, y = nextX, nextY
+	}
+}
+
+func rotate(matrix [][]int) {
+	w := len(matrix)
+	for y := range w / 2 {
+		for x := y; x < w-y-1; x++ {
+			rotateCell(matrix, x, y)
+		}
+	}
+}
+
+var _ = rotate