Ultraviolet A 11995 I can guess the data structure!

Uva_11995

If a data structure is still possible, you can simulate the operation on it until the error occurs.

# Include <stdio. h> # Include < String . H> # Include <Algorithm> # Define Maxd 1010 Int N, D, Max [ 4 * Maxd], Q [maxd], s [maxd];  Void  Init (){  For (D = 1 ; D <n + 2 ; D <= 1  ); Memset (max,  0 , Sizeof (Max [ 0 ]) * 2 * D );}  Void Update ( Int  I ){  For (; I ^ 1 ; I >>=1  ) Max [I > 1 ] = STD: max (MAX [I], Max [I ^ 1  ]);}  Void  Pop (){  Int  I;  For (I = 1 ; I < D ;){  If (Max [I < 1 ] = MAX [I]) I <=1  ;  Else I = I < 1 | 1  ;} MAX [I] = 0  , Update (I );}  Void  Solve (){  Int  I, op, X, front, rear, top, ISQ, ISS, ISP; front = Rear = Top = 0  ; ISQ = ISS = ISP =1  ;  For (I = 0 ; I <n; I ++ ) {Scanf (  "  % D  " , & OP ,& X );  If (OP = 1  ){  If (ISQ) Q [rear ++] = X;  If (ISS) s [top ++] = X;  If (ISP) Max [D + I] = x, update (D + I );}  Else  {  If  (ISQ ){  If (Front = rear) ISQ = 0  ;  Else  {  If (Q [Front]! = X) ISQ =0  ; ++ Front ;}}  If  (ISS ){  If (Top = 0 ) ISS = 0  ;  Else  { -- Top;  If (S [Top]! = X) ISS =0  ;}}  If  (ISP ){  If (Max [ 1 ]! = X) ISP = 0  ;  Else  Pop ();}}}  If (ISQ + ISS + ISP> 1  ) Printf (  " Not sure \ n  "  );  Else   If (ISQ + ISS + ISP = 0  ) Printf (  "  Impossible \ n  "  );  Else Printf ( "  % S \ n  " , ISQ? " Queue  " : (ISS? "  Stack  " : "  Priority queue  "  ));}  Int  Main (){  While (Scanf ( "  % D  " , & N) = 1 ) {Init (); solve ();}  Return   0  ;}