HDU 4010 query on the trees

Hdu_4010

Because cut and join are required for this question, link-cut-tree must be used for writing.

Both cut and join operations involve a basic operation, that is, converting a node into a root (makeroot). If you can write the makeroot operation successfully, cut and join are better done.

In fact, after the access (x) operation, if we want to use X as the root, we only need to "reverse" the parent-child relationship of the edge on this path, then, you just need to rotate X to the root, and then swap the position of the splay and the Left and Right sons of the Child tree, that is, marking the Rev (reverse.

In addition, pay attention to some details. For example, in some operations, if X is equal to Y, do you need to determine whether or not.

# Include <stdio. h> # Include < String . H># Define Maxd 300010 # Define Maxm 600010 # Define INF 0x7fffffff Int  N, first [maxd], E, next [maxm], V [maxm], Q [maxd];  Struct  Splay {  Int  PRE, ls, RS, key, Max, Rev, add;  Bool  Root;  Void Update (); Void Pushdown ();Void Zig ( Int ); Void Zag ( Int ); Void Splay ( Int  );  Void  RENEW () {Root = True  ; Pre = Ls = rs = 0  ; Rev = Add = 0 ;}} SP [maxd];  Int Max ( Int X, Int  Y ){  Return X> Y? X: Y ;}  Void  Splay: Update () {max = Max (max (SP [ls]. Max, SP [RS]. max), key );}  Void Makeadd ( Int Cur, Int  Delta ){ If  (Cur) SP [cur]. Add + = Delta, SP [cur]. Key + = delta, SP [cur]. MAX + = Delta ;}  Void Swap ( Int & X, Int & Y ){  Int  T; t = X, x = Y, y = T ;}  Void Makerev ( Int  Cur) {SP [cur]. Rev ^ =1  ; Swap (SP [cur]. ls, SP [cur]. RS );}  Void  Splay: Pushdown (){  If  (ADD) makeadd (LS, add), makeadd (RS, add), add = 0  ;  If  (REV) makerev (LS), makerev (RS), Rev = 0  ;}  Void Splay: Zig ( Int X ){  Int Y = RS, fa = Pre; RS = Sp [Y]. ls, SP [RS]. Pre = X; SP [Y]. ls = X, pre = Y; SP [Y]. Pre = Fa;  If  (Root) Root = False , SP [Y]. Root = True  ;  Else  SP [fa]. RS = X? SP [fa]. rs = Y: SP [fa]. ls =Y; Update ();}  Void Splay: zag ( Int  X ){  Int Y = ls, fa = Pre; LS = Sp [Y]. RS, SP [ls]. Pre = X; SP [Y]. RS = X, pre = Y; SP [Y]. Pre = Fa;  If  (Root) Root = False , SP [Y]. Root = True ;  Else  SP [fa]. RS = X? SP [fa]. rs = Y: SP [fa]. ls = Y; Update ();}  Void Splay: splay ( Int  X ){  Int  Y, Z;  For (Pushdown ();! Root;) {Y = Pre;  If (SP [Y]. Root) SP [Y]. Pushdown (), Pushdown (), SP [Y]. RS = X? SP [Y]. Zig (y): SP [Y]. Zag (y );  Else  {Z = SP [Y]. Pre; SP [Z]. Pushdown (), SP [Y]. Pushdown (), Pushdown ();  If (SP [Z]. rs = Y ){  If (SP [Y]. rs = X) SP [Z]. Zig (z), SP [Y]. Zig (y );  Else SP [Y]. Zag (Y), SP [Z]. Zig (z );}  Else  {  If (SP [Y]. ls = X) SP [Z]. Zag (z), SP [Y]. Zag (y );  Else  SP [Y]. Zig (Y), SP [Z]. Zag (z) ;}} Update ();}  Void Access ( Int  X ){  Int  FX; For (FX = x, x = 0 ; FX! = 0 ; X = FX, FX = SP [X]. PRE) {SP [FX]. splay (FX); SP [Sp [FX]. RS]. Root = True  ; SP [FX]. RS = X, SP [X]. Root = False  ; SP [FX]. Update ();}}  Void Makeroot ( Int  X) {access (x); SP [X]. splay (x); makerev (x );}  Void Prepare (){  Int I, j, X, rear = 0  ; SP [  0 ]. Max =- INF; Q [rear ++] = 1  ; SP [  1 ]. RENEW (), SP [ 1 ]. Max = Sp [ 1  ]. Key;  For (I = 0 ; I <rear; I ++) {X = Q [I];  For (J = first [X]; J! =- 1 ; J = Next [J])  If (V [J]! = SP [X]. PRE) {SP [V [J]. RENEW (), SP [V [J]. Pre = X, SP [V [J]. max = SP [V [J]. Key; Q [rear ++] = V [J] ;}}  Void Add ( Int X, Int Y) {v [E] = Y; next [E] = First [X], first [x] = e ++ ;}  Void  Init (){  Int  I, X, Y; memset (first, - 1 , Sizeof  (First); e = 0  ;  For (I = 1 ; I <n; I ++) {Scanf (  "  % D  " , & X ,& Y); add (x, y), add (Y, x );}  For (I = 1 ; I <= N; I ++ ) Scanf (  "  % D  " ,& SP [I]. Key); Prepare ();}  Void Join ( Int X,Int  Y ){  If (X = Y) {printf (  "  -1 \ n  "  );  Return  ;} Makeroot (x); makeroot (y );  If (SP [X]. Pre = 0  ) SP [Y]. Pre = X;  Else Printf (  "  -1 \ n  "  );}  Void Cut ( Int X, Int  Y) {makeroot (x); Access (y); SP [Y]. splay (y );  If (SP [X]. Pre = 0  ) Printf (  "  -1 \ n  " );  Else  {  Int T = SP [Y]. ls; SP [T]. Root = True , SP [T]. Pre = 0 , SP [Y]. ls = 0  ; SP [Y]. Update ();}}  Void Change ( Int X, Int Y, Int  Z ){ Int  FY; makeroot (y); makeroot (X );  If (SP [Y]. Pre = 0  ) Printf (  "  -1 \ n  "  );  Else  {Access (X );  For (FY = Y, y = 0 ; FY! = 0 ; Y = fy, FY =SP [Y]. PRE) {SP [FY]. splay (FY );  If (SP [FY]. Pre = 0  ) {Makeadd (SP [FY]. RS, Z), makeadd (Y, Z); SP [FY]. Key + = Z;} SP [Sp [FY]. RS]. Root = True  ; SP [FY]. RS = Y, SP [Y]. Root = False  ; SP [FY]. Update ();}}}  Void Query ( Int X,Int  Y ){  Int  FY;  If (X = Y) {SP [X]. splay (x); printf (  "  % D \ n  "  , SP [X]. Key );  Return  ;} Makeroot (y); makeroot (X );  If (SP [Y]. Pre = 0  ) Printf ( "  -1 \ n  "  );  Else  {Access (X );  For (FY = Y, y = 0 ; FY! = 0 ; Y = fy, FY = SP [Y]. PRE) {SP [FY]. splay (FY );  If (SP [FY]. Pre = 0  ) Printf (  " % D \ n  "  , Max (SP [Sp [FY]. RS]. max, SP [Y]. max), SP [FY]. key); SP [Sp [FY]. RS]. root = True  ; SP [FY]. RS = Y, SP [Y]. Root = False  ; SP [FY]. Update ();}}}  Void  Solve (){  Int  I, X, Y, Z, m, OP; scanf (  "  % D  " ,& M );  For (I = 0 ; I <m; I ++ ) {Scanf (  "  % D  " , & OP, & X ,& Y );  If (OP = 1  ) Join (x, y );  Else   If (OP = 2 ) Cut (x, y );  Else   If (OP = 3  ) {Scanf (  "  % D  " ,& Z); change (Y, Z, x );}  Else  Query (x, y );}}  Int  Main (){  While (Scanf ("  % D  " , & N) = 1  ) {Init (); solve (); printf (  "  \ N  "  );}  Return   0  ;}