Shuffle Cards（牛客第三场+splay）

题目：

题意：将1~n的数进行m次操作，每次操作将第pi位到pi+si-1位的数字移到第一位，求最后的排列。

思路：现在还没不会写splay，在知道这是splay模板题后找了一波别人的模板，虽然过了，但是感觉自己没学到什么，过几天去学一波splay，再回来把这题重写一次~

代码实现如下：

 #include <map>
 #include <set>
 #include <cmath>
 #include <ctime>
 #include <stack>
 #include <queue>
 #include <cstdio>
 #include <cctype>
 #include <bitset>
 #include <string>
 #include <vector>
 #include <cstring>
 #include <iostream>
 #include <algorithm>
 #include <functional>
 #include <bits/stdc++.h>
 #define debug(x) cout<<"["<<x<<"]";
 #define FIN freopen("input.txt","r",stdin);
 #define FOUT freopen("output.txt","w+",stdout);

 inline int read() {//读入挂
     int ret = , c, f = ;
     for(c = getchar(); !(isdigit(c) || c == '-'); c = getchar());
     if(c == '-')
         f = -, c = getchar();
     for(; isdigit(c); c = getchar())
         ret = ret *  + c - '';
     if(f < )
         ret = -ret;
     return ret;
 }

 const int MX = 1e5 + ;
 const int INF = 0x3f3f3f3f;

 int size[MX];
 int num[MX], col[MX], n, m;
 int son[MX][], fa[MX], root, sz;
 void Link(int x, int y, int c) {
     fa[x] = y;
     son[y][c] = x;
 }
 void push_up(int rt) {
     size[rt] = size[son[rt][]] + size[son[rt][]] + ;
 }
 void push_down(int rt) {
     if(col[rt]) {
         col[son[rt][]] ^= ;
         col[son[rt][]] ^= ;
         int x = son[rt][];
         son[rt][] = son[rt][];
         son[rt][] = x;
         col[rt] = ;
     }
 }
 void Rotate(int x, int c) {
     int y = fa[x];
     push_down(y);
     push_down(x);
     Link(x, fa[y], son[fa[y]][] == y);
     Link(son[x][!c], y, c);
     Link(y, x, !c);
     push_up(y);
 } /*把节点x旋转到g的下面*/

 void Splay(int x, int g) {
     push_down(x);    /*剪断[a,b]放到c后面*/
     while(fa[x] != g) {
         int y = fa[x], cx = son[y][] == x, cy = son[fa[y]][] == y;
         if(fa[y] == g)
             Rotate(x, cx);
         else {
             if(cx == cy)
                 Rotate(y, cy);
             else
                 Rotate(x, cx);
             Rotate(x, cy);
         }
     }
     push_up(x);
     if(!g)
         root = x;
 }
 void NewNode(int f, int &rt) {
     rt = ++sz;
     fa[rt] = f, size[rt] = ;
     son[rt][] = son[rt][] = col[rt] = ;
 } /*把第k个找出来，放到g的下面*/ int Select(int k, int g) {
     int rt = root;
     while(size[son[rt][]] != k) {
         if(size[son[rt][]] > k)
             rt = son[rt][];
         else
             k -= size[son[rt][]] + , rt = son[rt][];
         push_down(rt);
     }
     Splay(rt, g);
     return rt;
 }
 void Build(int l, int r, int &rt, int f) {
     if(l > r)
         return;
     int m = (l + r) >> , t;
     NewNode(f, rt);
     num[rt] = m;
     Build(l, m - , son[rt][], rt);
     Build(m + , r, son[rt][], rt);
     push_up(rt);
 }
 void Prepare(int n) {
     sz = ;
     NewNode(, root);
     num[] = ;
     NewNode(root, son[root][]);
     num[] = ;
     Build(, n, son[][], );
     Splay(, );
 }
 void Print(int rt, int &DFN) {
     if(!rt)
         return;
     push_down(rt);
     Print(son[rt][], DFN);
     if(num[rt])
         printf("%d%c", num[rt], ++DFN == n ? '\n' : ' ');
     Print(son[rt][], DFN);
 }
 void Flip(int l, int r) {
     Select(l - , );
     Select(r + , root);
     col[son[son[root][]][]] ^= ;
 }

 void Cut(int a, int b, int c) {
     Select(a - , );    /*平衡树操作*/
     Select(b + , root);
     int w = son[son[root][]][];
     son[son[root][]][] = ;
     Splay(son[root][], );
     Select(c, );
     Select(c + , root);
     son[son[root][]][] = w;
     Splay(son[root][], );
 }
 void NewNode(int f, int x, int &rt) {
     rt = ++sz;
     fa[rt] = f, size[rt] = ;
     son[rt][] = son[rt][] = ;
     num[rt] = x;
 }
 int Kth(int k) {
     int rt = root;
     while(size[son[rt][]] != k) {
         if(size[son[rt][]] > k)
             rt = son[rt][];
         else
             k -= size[son[rt][]] + , rt = son[rt][];
     }
     Splay(rt, );
     return num[rt];
 }
 void Insert(int x) {
     int rt = root;
     while(true) {
         int nxt = x > num[rt];
         if(!son[rt][nxt]) {
             NewNode(rt, x, son[rt][nxt]);
             Splay(sz, );
             return;
         }
         rt = son[rt][nxt];
     }
 }

 int main() {
     while(~scanf("%d%d", &n, &m)) {
         Prepare(n);
         int x, y;
         for(int i = ; i < m; i++) {
             scanf("%d%d", &x, &y);
             Cut(x, x + y - , );
         }
         int DFN = ;
         Print(root, DFN);
     }
     return ;
 }