import scala.annotation.tailrec import net.pushl.io.MyConsole // Document: http://www.scala-lang.org/api/current/#package // ----------------------------------------------------------------------------- class Solver(val stdio: MyConsole){ import stdio._ // shadow Console.~ @tailrec private def go(a: Int, b: Int, k: Int, acc: List[(Int,Int)]) : List[(Int,Int)] = { (a, b, k) match { case (0, 0, 0) => acc case (0, 0, 1) => acc case (0, 0, _) => go(a+1, b, k-1, (+1,0) :: acc) case (_, _, _) => { val x = if(a == 0) 0 else if(a < 0) +1 else -1 val y = if(b == 0) 0 else if(b < 0) +1 else -1 go(a+x, b+y, k-1, (x,y) :: acc) } } } def solve(a: Int, b: Int, t: Int) : Option[List[(Int,Int)]] = { if((a max b) > t) None else { val s = go(a,b,t,Nil) if(s.length == t) { Some(s) } else if(t >= 2) { val h = s.head val n = h match { case (0, 1) => (1,1) :: (-1,0) :: Nil case (0,-1) => (1,-1) :: (-1,0) :: Nil case (1, 0) => (1,1) :: (0,-1) :: Nil case (-1,0) => (-1,1) :: (0,-1) :: Nil case (1, 1) => (1,0) :: (0,1) :: Nil case (1,-1) => (1,0) :: (0,-1) :: Nil case (-1,1) => (-1,0) :: (0,1) :: Nil case (-1,-1) => (-1,0) :: (0,-1) :: Nil } Some(n ++ s.tail) }else{ None } } } def stringify(l: (Int,Int)) : String = { l match { case (0, 1) => "v" case (0,-1) => "^" case (1, 0) => "<" case (-1,0) => ">" case (1, 1) => "v<" case (1,-1) => "^<" case (-1,-1) => "^>" case (-1,1) => "v>" } } def main() : Unit = { val t, a, b = nextInt val ans = solve(b,a,t) match { case None => "NO" case Some(l) => "YES\n" ++ l.map(stringify).mkString("\n") } println(ans) } } // ----------------------------------------------------------------------------- // ----------------------------------------------------------------------------- object Main { def main(args: Array[String]) : Unit = { val console = new MyConsole(Console.in, Console.out, Console.err) val solver = new Solver(console) solver.main() console.flush() } } package net.pushl.io { import java.io.{BufferedReader, PrintWriter, PrintStream, PushbackReader} class MyConsole(val in: BufferedReader, val _out: PrintStream, val err: PrintStream) { // PrintWriter do not flush automatically val out = new PrintWriter(_out,false) // If argument is null, there are ambiguous which function will be called def print(obj: Any) = out.print(if(obj == null) "null" else obj.toString) def println() = out.println() def println(obj: Any) = out.println(obj) def printf(text: String, args: Any*) = out.printf(text.format(args : _*)) // NOTE: YOU MUST FLUSH BEFORE END OF MAIN def flush() = out.flush() def debugln(obj: Any) = err.println("\u001b[36m" + obj + "\u001b[0m") def readIntVector() : Vector[Int] = parseLineToVector(() => nextInt) def readLongVector() : Vector[Long] = parseLineToVector(() => nextLong) def readStringVector() : Vector[String] = parseLineToVector(() => nextString) def nextInt() : Int = nextLong().toInt def nextBigInt() : BigInt = BigInt(nextString()) def nextBigDecimal( ) : BigDecimal = BigDecimal(nextString()) def nextDouble() : Double = nextString().toDouble def nextLong() : Long = { if(!goNextValuable()) throw new NoSuchElementException("Reading long failed") val sgn = if(peek == '-') -1l else 1 if(sgn == -1l) ignore(read()) if(peek < '0' || '9' < peek) throw new NumberFormatException(s"readLong found only '-' or no number") @tailrec def readLong(next: Int, cur: Long) : Long = if('0' <= next && next <= '9'){ ignore(read()) // is equal to next readLong(peek, cur*10 + next-'0') } else if(isEnd(next) || isSpaceOrControl(next)) sgn*cur else throw new NumberFormatException(s"readLong found strange byte $next") val res = readLong(peek,0) skipTrailingSpaces() res } def nextString() : String = { if(!goNextValuable()) throw new NoSuchElementException("Reading String failed") val builder = new StringBuilder @tailrec def appendCode(next: Int) : String = { if(isEnd(next) || isSpaceOrControl(next)){ builder.toString }else{ builder.append(read().toChar) // here we skip. appendCode(peek) } } val res = appendCode(peek) skipTrailingSpaces() res } // TODO: refactoring to marge nextString def readLine() : String = { if(isEnd(peek)) throw new NoSuchElementException("Reading Line failed") skipNewline() val builder = new StringBuilder @tailrec def appendCode(next: Int) : String = { if(isEnd(next) || isNewLine(next)){ builder.toString }else{ builder.append(next.toChar) appendCode(read()) } } appendCode(read()) } // helpers private def ignore[T](x: => T) : Unit = { x; () } private[this] var peeked: Option[Int] = None private[this] var is_first = true protected def read() = { val res = peeked match { case None => in.read() case Some(a) => { peeked = None; a } } is_first = false res } private def peek() = peeked match { case None => { val res = in.read() peeked = Some(res) res } case Some(a) => a } private def isEnd(c: Int) = c == -1 private def isCR(c: Int) = c == 13 private def isLF(c: Int) = c == 10 private def isNewLine(c: Int) = isLF(c) || isCR(c) private def isThereReadable() = !isEnd(peek) private def isSpaceOrControl(c: Int) = (0 <= c && c <= 32) || c == 127 @tailrec final private def goNextNotSpaceNorControl() : Unit = if(isSpaceOrControl(peek)){ ignore(read()) goNextNotSpaceNorControl() } final private def skipTrailingSpaces() : Unit = { @tailrec def skipTrailingSpacesAux() : Unit = { if(!isNewLine(peek) && isSpaceOrControl(peek)){ ignore(read()) skipTrailingSpacesAux() } } skipTrailingSpacesAux() } final private def skipNewline() : Unit = if(!is_first){ if(isCR(peek)) ignore(read()) if(isLF(peek)) ignore(read()) } private def goNextValuable() : Boolean = { goNextNotSpaceNorControl() isThereReadable() } private def parseLineToVector[X](parser: () => X) : Vector[X] = { import scala.collection.immutable.VectorBuilder val vb = new VectorBuilder[X]() skipNewline() @tailrec def parseLineToVectorAux() : Vector[X] = if(isNewLine(peek) || isEnd(peek)) { vb.result }else{ vb += parser() parseLineToVectorAux() } parseLineToVectorAux() } } }