Splay解决区间问题[区间切割，区间翻转]

区间翻转：由于以root为根的树的中序遍历表示该区间，那么翻转只要递归的交换左右子树即可，加入lazy思想，降低时间复杂度。

Tips：做区间翻转的时候rev[rt]的含义是——以rt为根的子树所表示的区间是否将要被翻转，目前并没有执行翻转操作，如果改成先翻转，再标记，就会出现大问题。

Code：没用的push_down写多了。

/*http://acm.hdu.edu.cn/showproblem.php?pid=3487*/
/*splay区间切割+翻转*/
#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
const int MAXN = 333333;
#define m_set(ptr,v,type,size) memset(ptr,v,sizeof(type)*size)
#define loop(begin,end) for(int i=begin;i<end;i++)
class SplayTree{
#define l(x) (ch[x][0])
#define r(x) (ch[x][1])
#define mid(x,y) ((x+y)>>1)
public:
int ch[MAXN][2],pre[MAXN];
int sz[MAXN],val[MAXN],rev[MAXN],a[MAXN];
int root,tot;
void init(){
m_set(ch,0,int,MAXN*2);
m_set(pre,0,int,MAXN);
m_set(sz,0,int,MAXN);
m_set(val,0,int,MAXN);
m_set(rev,0,int,MAXN);
root = tot = 0;
}
void read(int n){
a[1] = a[n+2] = 0;
loop(2,n+2){ a[i] = i-1; }
}
void push_up(int rt){
sz[rt] = sz[l(rt)]+sz[r(rt)]+1;
}
void swap(int &x,int &y){
int tmp = x;
x = y;
y = tmp;
}
void push_down(int rt){
if(rt&&rev[rt]){
swap(l(rt),r(rt));
if(l(rt)) rev[l(rt)] ^= 1;
if(r(rt)) rev[r(rt)] ^= 1;
rev[rt] = 0;
}
}
void rotate(int x,int f){
int y = pre[x];
push_down(x);
push_down(y);
ch[y][!f] = ch[x][f];
if(ch[y][!f]) pre[ch[y][!f]] = y;
push_up(y);
if(pre[y]) ch[pre[y]][r(pre[y])==y] = x;
pre[x] = pre[y];
ch[x][f] = y;
pre[y] = x;
}
void splay(int x,int goal){
push_down(x);
while(pre[x]!=goal){
int y = pre[x], z = pre[pre[x]];
if(z==goal){
rotate(x,l(y)==x);
}else{
int f = l(z)==y;
if(ch[y][!f]==x){
rotate(y,f); rotate(x,f);
}else{
rotate(x,!f); rotate(x,f);
}
}
}
push_up(x);
if(goal==0) root = x;
}
void rotateTo(int k,int goal){
int x = root;
while(1){
push_down(x);
int tmp = sz[l(x)]+1;
if(k==tmp) break;
else if(k<tmp) x = l(x);
else{
k -= tmp;
x = r(x);
}
}
splay(x,goal);
}
void buildTree(int l,int r,int &rt,int f){
if(l>r)return;
int m = mid(l,r);
rt = ++tot;
val[rt] = a[m];
pre[rt] = f;
buildTree(l,m-1,l(rt),rt);
buildTree(m+1,r,r(rt),rt);
push_up(rt);
}
void rangeCut(int l,int r,int goal){
rotateTo(l-1,0);
rotateTo(r+1,root);
push_down(r(root));
int x = l(r(root));
l(r(root)) = 0;
pre[x] = 0;
push_up(r(root));
push_up(root);
rotateTo(goal,0);
rotateTo(goal+1,root);
push_down(r(root));
l(r(root)) = x;
pre[x] = r(root);
push_up(r(root));
push_up(root);
}
void rangeFlip(int l,int r){
rotateTo(l-1,0);
rotateTo(r+1,root);
push_down(r(root));
int x = l(r(root));
rev[x] ^= 1;
}
void dfs(int rt,int &size){
if(!rt) return;
push_down(rt);
dfs(l(rt),size);
a[size++] = val[rt];
dfs(r(rt),size);
}
/////////////////debug///////////////////////

}spt;
int main(){
int n,m;
while(scanf("%d%d",&n,&m),!(n<0&&m<0)){
spt.init();
spt.read(n);
spt.buildTree(1,n+2,spt.root,0);
char op[5]; int a,b,c;
while(m--){
scanf("%s%d%d",op,&a,&b);
if(op[0]=='C'){
scanf("%d",&c);
spt.rangeCut(a+1,b+1,c+1);
}else{
spt.rangeFlip(a+1,b+1);
}
}
n = 0;
spt.dfs(spt.root,n);
loop(1,n-1){
if(i!=1)printf(" ");
printf("%d",spt.a[i]);
}
printf("\n");
}
return 0;
}