3600: 没有人的算术

来源:互联网 发布:易语言gh0st远控源码 编辑:程序博客网 时间:2024/04/28 01:43

3600: 没有人的算术

Time Limit: 20 Sec  Memory Limit: 128 MB
Submit: 616  Solved: 280
[Submit][Status][Discuss]

Description

Input

Output

Sample Input

Sample Output

HINT

Source

湖北省队互测 Week1

[Submit][Status][Discuss]

可以发现,每时每刻新增的元素加入之前元素组成的集合中,
新集合内的元素两两之间一定可以找出严格的大小关系
考虑用某数据结构维护已知集合内的元素,支持O(logn)查询,插入之类
考虑当前新增第k个元素,前k - 1个元素的大小关系已经能在这个数据结构里体现了
不妨给每个点一个实数,这样之前元素的比较就可以直接通过实数比较进行
实数如何选取?给予每个节点一个区间[L,R],定义该节点的势能phi[x] = (L[x] + R[x]) / 2
这样通过势能比较就行了,能够比较,能够查询,此题的大部分操作就已经解决
询问的话,用个线段树维护维护就完成了
最后,数据结构的选择,不妨使用替罪羊树,因为区间的限制,使得节点之间的关系要相对静态
替罪羊树的话,就是选取一个定值alpha,对于某个节点,如果其较大的子树的大小超过该点size * alpha,
则标记这个点,每次插入操作,将标记最浅的那个子树暴力重构成一棵完全二叉树

具体的证明可见CLJ2013年的论文

第一遍写的时候fa[]和rt没有维护好(重构可能改变的东西= =)
人傻不能怪社会系列。。。

#include<iostream>#include<cstdio>#include<algorithm>#include<cmath>#include<cstring>#include<vector>#include<queue>#include<set>#include<map>#include<stack>#include<bitset>#include<ext/pb_ds/priority_queue.hpp>using namespace std;const int maxn = 1E5 + 10;const int maxm = 5E5 + 50;const int T = 4;typedef double DB;const DB alpha = 0.666;const DB eps = 1E-9;DB lp,rp,siz[maxm],phi[maxm],L[maxm],R[maxm];int n,m,cnt,rt,tp,p,Now,Ans,fa[maxm],id[maxn*T],pos[maxn*T],ch[maxm][2],s[maxm],lc[maxm],rc[maxm];int getint(){char ch = getchar(); int ret = 0;while (ch < '0' || '9' < ch) ch = getchar();while ('0' <= ch && ch <= '9')ret = ret*10 + ch - '0',ch = getchar();return ret;}int getcom(){char ch = getchar();while (ch != 'C' && ch != 'Q') ch = getchar();return ch == 'C' ? 1 : 2;}int cmp(const int &x,const int &y){if (lc[x] == lc[y] && rc[x] == rc[y]) return 2;if (lc[x] == lc[y]) return phi[rc[x]] < phi[rc[y]] ? 1 : 0;return phi[lc[x]] < phi[lc[y]] ? 1 : 0;}void maintain(int o){int ls = (o<<1),rs = (o<<1|1);int d = cmp(id[ls],id[rs]);if (d == 1) pos[o] = pos[rs],id[o] = id[rs];else pos[o] = pos[ls],id[o] = id[ls];}void Build(int o,int l,int r){if (l == r) {id[o] = 1; pos[o] = l; return;}int mid = (l + r) >> 1;Build(o<<1,l,mid); Build(o<<1|1,mid+1,r);maintain(o);}void Modify(int o,int l,int r,int k,int ID){if (l == r) {id[o] = ID; return;}int mid = (l + r) >> 1;if (k <= mid) Modify(o<<1,l,mid,k,ID);else Modify(o<<1|1,mid+1,r,k,ID);maintain(o);}int Get_id(int o,int l,int r,int k){if (l == r) return id[o]; int mid = (l + r) >> 1;if (k <= mid) return Get_id(o<<1,l,mid,k);else return Get_id(o<<1|1,mid+1,r,k);}void Get_pos(int o,int l,int r,int ql,int qr){if (ql <= l && r <= qr){int d = cmp(id[o],Now);if (d == 0) Now = id[o],Ans = pos[o];else if (d == 2) Ans = min(Ans,pos[o]);return;}int mid = (l + r) >> 1;if (ql <= mid) Get_pos(o<<1,l,mid,ql,qr);if (qr > mid) Get_pos(o<<1|1,mid+1,r,ql,qr);}int Query(int x,int now){if (!x) return x;int d = cmp(x,now);if (d == 2) return x;return Query(ch[x][d],now);}void Insert(int &x,int now,DB LP,DB RP){if (!x){x = now; phi[x] = (LP + RP) / 2.00;L[x] = LP; R[x] = RP; siz[x] = 1.00; return;}DB mid = (LP + RP) / 2.00; int d = cmp(x,now);if (!d) Insert(ch[x][d],now,L[x],mid);else Insert(ch[x][d],now,mid,R[x]);fa[ch[x][d]] = x; siz[x] = siz[ch[x][0]] + siz[ch[x][1]] + 1.00;if (siz[ch[x][d]] >= alpha * siz[x]) p = x,lp = L[x],rp = R[x];}void Dfs(int x){if (!x) return; Dfs(ch[x][0]);s[++tp] = x; Dfs(ch[x][1]);}int Build_tree(int l,int r,DB LP,DB RP){if (l > r) return 0;int mid = (l + r) >> 1;int k = s[mid]; phi[k] = (LP + RP) / 2.00;ch[k][0] = Build_tree(l,mid-1,LP,phi[k]);ch[k][1] = Build_tree(mid+1,r,phi[k],RP);siz[k] = 1.00; L[k] = LP; R[k] = RP;for (int i = 0; i < 2; i++)if (ch[k][i]) fa[ch[k][i]] = k,siz[k] += siz[ch[k][i]];return k;}void Rebuild(){tp = 0; Dfs(p);int q = fa[p],now = Build_tree(1,tp,lp,rp);if (!q) rt = now,fa[now] = 0;else ch[q][ch[q][1] == p] = now,fa[now] = q;}int main(){#ifdef DMCfreopen("DMC.txt","r",stdin);#endifn = getint(); m = getint(); rt = cnt = 1;R[rt] = 1E9; phi[rt] = (L[rt] + R[rt]) / 2.00; Build(1,1,n);while (m--){int typ = getcom(),l,r;l = getint(); r = getint();if (typ == 1){int k = getint(); ++cnt;lc[cnt] = Get_id(1,1,n,l);rc[cnt] = Get_id(1,1,n,r);int ret = Query(rt,cnt);if (ret) Modify(1,1,n,k,ret),--cnt;else{Modify(1,1,n,k,cnt);p = 0; Insert(rt,cnt,L[rt],R[rt]);if (p) Rebuild();}}else{Now = 1; Ans = maxn;Get_pos(1,1,n,l,r); printf("%d\n",Ans);}}return 0;}

0 0