HDU 3487 Play with Chain (Splay)

题意：给定一个序列，1 2 3 ... n，然后有两种操作。

第一种是 CUT x y z ，把第 x 到 第 y 个数剪切下来，然后放到第 z 个后面。

第二种是 FLIP x y 把 第 x 到第 y 个反转。

最后输出序列。

析：几乎就是裸的Splay，就是两种操作，剪切和反转，用splay很好维护，剪切的时候不要一个结点一个结点的剪，要直接剪切一棵子树。粘贴也是。

代码如下：

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include <cstdio>
#include <string>
#include <cstdlib>
#include <cmath>
#include <iostream>
#include <cstring>
#include <set>
#include <queue>
#include <algorithm>
#include <vector>
#include <map>
#include <cctype>
#include <cmath>
#include <stack>
#include <sstream>
#define debug() puts("++++");
#define gcd(a, b) __gcd(a, b)
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define freopenr freopen("in.txt", "r", stdin)
#define freopenw freopen("out.txt", "w", stdout)
using namespace std;

typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> P;
const int INF = 0x3f3f3f3f;
const LL LNF = 1e16;
const double inf = 0x3f3f3f3f3f3f;
const double PI = acos(-1.0);
const double eps = 1e-8;
const int maxn = 3e5 + 10;
const int mod = 1e9 + 7;
const int dr[] = {-1, 0, 1, 0};
const int dc[] = {0, 1, 0, -1};
const char *de[] = {"0000", "0001", "0010", "0011", "0100", "0101", "0110", "0111", "1000", "1001", "1010", "1011", "1100", "1101", "1110", "1111"};
int n, m;
const int mon[] = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
const int monn[] = {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
inline bool is_in(int r, int c){
return r >= 0 && r < n && c >= 0 && c < m;
}

#define Key_value ch[ch[root][1]][0]
int pre[maxn], ch[maxn][2], key[maxn], sz[maxn];
int rev[maxn];
int root, tot1;
int a[maxn], b[maxn];
int cnt;

void NewNode(int &rt, int fa, int val){
rt = ++tot1;
pre[rt] = fa;
ch[rt][0] = ch[rt][1] = 0;
key[rt] = val;
rev[rt] = 0;
sz[rt] = 1;
}

void update(int rt){
if(!rt)  return ;
swap(ch[rt][0], ch[rt][1]);
rev[rt] ^= 1;
}

void push_up(int rt){
sz[rt] = sz[ch[rt][0]] + sz[ch[rt][1]] + 1;
}

void push_down(int rt){
if(rev[rt]){
update(ch[rt][0]);
update(ch[rt][1]);
rev[rt] = 0;
}
}

void Build(int &rt, int l, int r, int fa, int *a){
if(l > r)  return ;
int m = l + r >> 1;
NewNode(rt, fa, a[m]);
Build(ch[rt][0], l, m-1, rt, a);
Build(ch[rt][1], m+1, r, rt, a);
push_up(rt);
}

void Init(){
root = tot1 = 0;
ch[root][0] = ch[root][1] = sz[root] = pre[root] = 0;
rev[root] = key[root] = 0;
NewNode(root, 0, -1);
NewNode(ch[root][1], root, -1);
Build(Key_value, 1, n, ch[root][1], a);
push_up(ch[root][1]);
push_up(root);
}

void Rotate(int x, int kind){
int y = pre[x];
push_down(y);
push_down(x);
ch[y][!kind] = ch[x][kind];
pre[ch[x][kind]] = y;
if(pre[y])  ch[pre[y]][ch[pre[y]][1]==y] = x;
pre[x] = pre[y];
ch[x][kind] = y;
pre[y] = x;
push_up(y);
}

void Splay(int r, int goal){
push_down(r);
while(pre[r] != goal){
if(pre[pre[r]] == goal){
push_down(pre[r]);
push_down(r);
Rotate(r, ch[pre[r]][0] == r);
}
else{
push_down(pre[pre[r]]);
push_down(pre[r]);
push_down(r);
int y = pre[r];
int kind = ch[pre[y]][0] == y;
if(ch[y][kind] == r){
Rotate(r, !kind);
Rotate(r, kind);
}
else{
Rotate(y, kind);
Rotate(r, kind);
}
}
}
push_up(r);
if(goal == 0)  root = r;
}

int Get_kth(int rt, int k){
push_down(rt);
int t = sz[ch[rt][0]] + 1;
if(t == k)  return rt;
if(t > k)  return Get_kth(ch[rt][0], k);
return Get_kth(ch[rt][1], k-t);
}

void Reverse(int pos, int tot){
Splay(Get_kth(root, pos), 0);
Splay(Get_kth(root, pos+tot+1), root);
update(Key_value);
push_up(ch[root][1]);
push_up(root);
}

void Cut(int x, int y, int z){
int tot = y - x + 1;
Splay(Get_kth(root, x), 0);
Splay(Get_kth(root, x+tot+1), root);
int t = Key_value;
Key_value = 0;
push_up(ch[root][1]);
push_up(root);
Splay(Get_kth(root, z+1), 0);
Splay(Get_kth(root, z+2), root);
Key_value = t;
pre[t] = ch[root][1];
push_up(ch[root][1]);
push_up(root);
}

void print(int rt){
if(!rt)  return ;
push_down(rt);
print(ch[rt][0]);
if(cnt > 0 && cnt <= n){
if(cnt > 1)  putchar(' ');
printf("%d", key[rt]);
}
++cnt;
print(ch[rt][1]);
}

int main(){
for(int i = 1; i < maxn; ++i)  a[i] = i;
while(scanf("%d %d", &n, &m) == 2 && n + m > 0){
Init();
char s[10];
while(m--){
int x, y, z;
scanf("%s %d %d", s, &x, &y);
if(s[0] == 'C'){
scanf("%d", &z);
Cut(x, y, z);
}
else  Reverse(x, y-x+1);
}
cnt = 0;
print(root);
printf("\n");
}
return 0;
}