H、智乃的树旋转(hard version)

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whiteawll 2022-08-16 14:53:23 博主文章分类：练习题目 ©著作权

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#include<bits/stdc++.h>
using namespace std;

#define rep(i,l,r) for(int i=(l);i<=(r);i++)
#define per(i,l,r) for(int i=(l);i>=(r);i--)
#define ll long long
#define pii pair<int, int>
#define mset(s,t) memset(s,t,sizeof(t))
#define mcpy(s,t) memcpy(s,t,sizeof(t))
#define fir first
#define pb push_back
#define sec second

inline int read () {
   int x = 0, f = 0;
   char ch = getchar();
   while (!isdigit(ch)) f |= ch=='-',ch= getchar();
   while (!isdigit(ch)) x = x * 10 + ch - '0', ch = getchar();
   return f?-x:x;
}
template<typename T> void print(T x) {
   if (x < 0) putchar('-'), x = -x;
   if (x >= 10) print(x/10);
   putchar(x % 10 + '0');
}
const int N = 1e5 + 10;
struct  tree {
    int fa;
    int ch[2];
}t[N], a[N];
int n;
vector<int> ans;
bool vis[N] = {1};
void rot (int root) {
   int fa = t[root].fa;
   int gfa = t[fa].fa;
   int t1 = (root != t[fa].ch[0]);
   int t2 = (fa != t[gfa].ch[0]);
   int ch = t[root].ch[1^t1];
   t[root].fa = gfa;
   t[root].ch[1^t1] = fa;
   //折一下 
   t[fa].ch[0^t1] = ch;
   //不折 
   t[fa].fa = root;
   t[ch].fa = fa;
   t[gfa].ch[0^t2] = root;
   //不折 
   return;
}
void splay (int root) {
   while (!vis[t[root].fa]) {
      ans.pb(root);
      rot(root);
   }
}
void dfs (int u) {
   splay(u);
   vis[u] = 1;
   if (a[u].ch[0]) dfs(a[u].ch[0]);
   if (a[u].ch[1]) dfs(a[u].ch[1]);
}
int input_tree(tree* t, int n)
{
    int x, y;
    std::vector<bool> v(n + 1, true);
    for (int i = 1; i <= n; ++i)
    {
        scanf("%d %d", &x, &y);
        v[x] = v[y] = false;
        t[i].ch[0] = x;
        t[i].ch[1] = y;
        if (x)t[x].fa = i;
        if (y)t[y].fa = i;
    }
    for (int i = 1; i <= n; ++i)
    {
        if (v[i])return i;
    }
    return -1;
}

void solve() {
   cin >> n;
   int root_a = input_tree(a, n);
   int root_t = input_tree(t, n);
    dfs(root_a);
   cout << ans.size() << endl;
   for (auto t : ans) cout << t << endl;
}
int main () {
    solve();
    return 0;
}