From b57c4abbd177f72de719b5965a02d5f9f2010a83 Mon Sep 17 00:00:00 2001
From: TooYoungTooSimp <6648049+TooYoungTooSimp@users.noreply.github.com>
Date: Mon, 3 Apr 2017 11:05:06 +0800
Subject: [PATCH] bzoj 2049 LCT

---
 OnlineJudges/lydsy/2049.cpp | 102 ++++++++++++++++++++++++++++++++++++
 1 file changed, 102 insertions(+)
 create mode 100644 OnlineJudges/lydsy/2049.cpp

diff --git a/OnlineJudges/lydsy/2049.cpp b/OnlineJudges/lydsy/2049.cpp
new file mode 100644
index 0000000..85ab838
--- /dev/null
+++ b/OnlineJudges/lydsy/2049.cpp
@@ -0,0 +1,102 @@
+#include <cctype>
+#include <cstdio>
+template <typename T>
+inline void swap(T &x, T &y)
+{
+    T t = x;
+    x = y;
+    y = t;
+}
+inline void read(int &x)
+{
+    int ch = x = 0;
+    while (!isdigit(ch)) ch = getchar();
+    for (; isdigit(ch); ch = getchar()) x = x * 10 + ch - '0';
+}
+struct node
+{
+    bool rev;
+    node *fa, *ch[2];
+    int dir() { return fa == 0 ? -1 : this == fa->ch[1]; }
+    bool isRoot() { return fa == 0 || (fa->ch[0] != this && fa->ch[1] != this); }
+} T[10001];
+inline void push_down(node *x)
+{
+    if (x == 0) return;
+    if (x->rev)
+    {
+        swap(x->ch[0], x->ch[1]);
+        if (x->ch[0]) x->ch[0]->rev ^= 1;
+        if (x->ch[1]) x->ch[1]->rev ^= 1;
+        x->rev = false;
+    }
+}
+void push_down_recursive(node *x)
+{
+    if (!x->isRoot()) push_down_recursive(x->fa);
+    push_down(x);
+}
+inline void liftup(node *x)
+{
+    if (x == 0 || x->isRoot()) return;
+    int d = x->dir();
+    node *f = x->fa, *ff = f->fa, *c = x->ch[d ^ 1];
+    if (ff && !f->isRoot()) ff->ch[f->dir()] = x;
+    x->fa = ff, f->fa = x, x->ch[d ^ 1] = f, f->ch[d] = c;
+    if (c) c->fa = f;
+}
+inline void Splay(node *x)
+{
+    push_down_recursive(x);
+    for (; !x->isRoot(); liftup(x))
+        if (!x->fa->isRoot())
+            liftup((x->dir() ^ x->fa->dir()) ? x : x->fa);
+}
+inline void access(node *x)
+{
+    for (node *y = 0; x; y = x, x = x->fa)
+    {
+        Splay(x), x->ch[1] = y;
+        if (y) y->fa = x;
+    }
+}
+inline node *findRoot(node *x)
+{
+    access(x), Splay(x);
+    while (push_down(x), x->ch[0]) x = x->ch[0];
+    Splay(x);
+    return x;
+}
+inline void makeRoot(node *x)
+{
+    access(x), Splay(x);
+    x->rev ^= 1;
+}
+inline void Link(node *x, node *f)
+{
+    makeRoot(x);
+    x->fa = f;
+}
+inline void Cut(node *x, node *y)
+{
+    makeRoot(x), access(y), Splay(y);
+    x->fa = y->ch[0] = 0;
+}
+int main()
+{
+    int n, m, u, v;
+    read(n), read(m);
+    while (m--)
+    {
+        int op = getchar();
+        while (!isupper(op)) op = getchar();
+        read(u), read(v);
+        if (op == 'Q')
+            puts(findRoot(&T[u]) == findRoot(&T[v]) ? "Yes" : "No");
+        if (op == 'C')
+            Link(&T[u], &T[v]);
+        if (op == 'D')
+            Cut(&T[u], &T[v]);
+    }
+    return 0;
+}
\ No newline at end of file