BZOJ1078: [SCOI2008]斜堆

题目：http://www.lydsy.com/JudgeOnline/problem.php?id=1078

每一次进入的点一定是一个极左节点，然后将它所处在的整棵树左右翻转。加上一些情况的处理。

#include<cstring>
#include<iostream>
#include<algorithm>
#include<cstdlib>
#include<cstdio>
#include<cmath>
#include<queue>
#define rep(i,l,r) for (int i=l;i<=r;i++)
#define down(i,l,r) for (int i=l;i>=r;i--)
#define clr(x,y) memset(x,y,sizeof(x))
#define maxn 2005
#define eps 1e-3
#define ll long long
#define inf (1LL<<50)
using namespace std;
int fa[maxn],l[maxn],r[maxn],ans[maxn],n,tot,root;
int read(){
    int x=,f=; char ch=getchar();
    while (!isdigit(ch)) {if (ch=='-') f=-; ch=getchar();}
    while (isdigit(ch)) {x=x*+ch-''; ch=getchar();}
    return x*f;
}
void solve(){
    int x=root;
    while (r[x]!=-) x=l[x];
    int t=l[x];
    if (t!=-&&l[t]==-&&r[t]==-) x=t;
    ans[++tot]=x;
    if (x==root) root=l[root];
    int f=fa[x];
    if (f!=-) l[f]=l[x],fa[l[f]]=f;
    while (f!=-) swap(l[f],r[f]),f=fa[f];
}
int main(){
    n=read();
    fa[]=-;
    clr(l,-); clr(r,-);
    rep(i,,n) {
        int x=read();
        if (x>=) fa[i]=x-,r[x-]=i;
        else fa[i]=x,l[x]=i;
    }
    rep(i,,n) solve();
    while (tot) printf("%d ",ans[tot--]);
    return ;
}