PROC Generate(BYTE size CHAR ARRAY s)
  BYTE i,half

  s(0)=size
  half=size RSH 1

  FOR i=1 TO half
  DO s(i)='[ OD

  FOR i=half+1 TO size
  DO s(i)='] OD
RETURN

PROC Shuffle(CHAR ARRAY s)
  BYTE i,j,k,n,len,tmp

  len=s(0)
  n=Rand(len+1)
  FOR k=1 TO n
  DO
    i=Rand(len)+1
    j=Rand(len)+1
    tmp=s(i)
    s(i)=s(j)
    s(j)=tmp
  OD
RETURN

BYTE FUNC Balanced(CHAR ARRAY s)
  INT i,lev

  lev=0
  FOR i=1 TO s(0)
  DO
    IF s(i)='[ THEN
      lev==+1
    ELSE
      lev==-1
    FI

    IF lev<0 THEN
      RETURN (0)
    FI
  OD

  IF lev#0 THEN
    RETURN (0)
  FI
RETURN (1)

PROC Main()
  CHAR ARRAY s(20)
  BYTE i,b

  FOR i=0 TO 20 STEP 2
  DO
    Generate(i,s)
    Shuffle(s)
    b=Balanced(s)

    IF s(0)=0 THEN
      Print("(empty)")
    ELSE
      Print(s)
    FI
    Print(" is ")
    IF b=0 THEN
      Print("not ")
    FI
    PrintE("balanced")
  OD
RETURN