SPOJ QTREE7 lct

题目链接

已经在代码中注释了变量含义，感觉不难

inf好像不止|1e9| inf设成0x3f 才过。。

#include <iostream>#include <fstream>#include <string>#include <time.h>#include <vector>#include <map>#include <queue>#include <algorithm>#include <stack>#include <cstring>#include <cmath>#include <set>#include <vector>using namespace std;template <class T>inline bool rd(T &ret) {char c; int sgn;if (c = getchar(), c == EOF) return 0;while (c != '-' && (c<'0' || c>'9')) c = getchar();sgn = (c == '-') ? -1 : 1;ret = (c == '-') ? 0 : (c - '0');while (c = getchar(), c >= '0'&&c <= '9') ret = ret * 10 + (c - '0');ret *= sgn;return 1;}template <class T>inline void pt(T x) {if (x <0) {putchar('-');x = -x;}if (x>9) pt(x / 10);putchar(x % 10 + '0');}typedef long long ll;typedef pair<int, int> pii;const int N = 500005;const int inf = 0x3f3f3f3f;inline int First(multiset<int>&x) {return *x.rbegin();}inline int Second(multiset<int>&x) {multiset<int>::reverse_iterator it = x.rbegin();it++; return *it;}inline void Erase(multiset<int>&x, int val) {x.erase(x.find(val));}struct Node *null;struct Node {Node *fa, *ch[2];int id;multiset<int>s[2];//s[0] this虚边所连的所有子树的连续白色点的最大值（不是链）int col;int ls[2], rs[2], siz, val;//ls[0]是对于这条链 最上端向下的连续白色点数int Ls[2], Rs[2];//Ls[0]是对于这棵子树 与最上端点相连的连续白色点的最大值bool rev;inline void clear(int _col, int _val, int _id) {fa = ch[0] = ch[1] = null;siz = 1;rev = 0;id = _id;col = _col;val = _val;for (int i = 0; i < 2; i++) {ls[i] = rs[i] = 0;Ls[i] = Rs[i] = -inf;s[i].clear();s[i].insert(-inf);}}inline void push_up() {if (this == null)return;siz = ch[0]->siz + ch[1]->siz + 1;for (int i = 0; i < 2; i++) {ls[i] = ch[0]->ls[i], rs[i] = ch[1]->rs[i];Ls[i] = ch[0]->Ls[i], Rs[i] = ch[1]->Rs[i];if (ch[0]->ls[i] == ch[0]->siz && i == col) {ls[i] = ch[0]->siz + 1 + ch[1]->ls[i];Ls[i] = max(Ls[i], val);Ls[i] = max(Ls[i], First(s[i]));Ls[i] = max(Ls[i], ch[1]->Ls[i]);}if (ch[1]->rs[i] == ch[1]->siz && i == col) {rs[i] = ch[1]->siz + 1 + ch[0]->rs[i];Rs[i] = max(Rs[i], val);Rs[i] = max(Rs[i], First(s[i]));Rs[i] = max(Rs[i], ch[0]->Rs[i]);}}}inline void push_down() {if (rev) {ch[0]->flip();ch[1]->flip();rev = 0;}}inline void setc(Node *p, int d) {ch[d] = p;p->fa = this;}inline bool d() {return fa->ch[1] == this;}inline bool isroot() {return fa == null || fa->ch[0] != this && fa->ch[1] != this;}inline void flip() {if (this == null)return;swap(ch[0], ch[1]);rev ^= 1;}inline void go() {//从链头开始更新到thisif (!isroot())fa->go();push_down();}inline void rot() {Node *f = fa, *ff = fa->fa;int c = d(), cc = fa->d();f->setc(ch[!c], c);this->setc(f, !c);if (ff->ch[cc] == f)ff->setc(this, cc);else this->fa = ff;f->push_up();}inline Node*splay() {go();while (!isroot()) {if (!fa->isroot())d() == fa->d() ? fa->rot() : rot();rot();}push_up();return this;}inline Node* access() {//access后this就是到根的一条splay，并且this已经是这个splay的根了for (Node *p = this, *q = null; p != null; q = p, p = p->fa) {p->splay();if (p->ch[1] != null)for (int i = 0;i < 2;i++){p->s[i].insert(p->ch[1]->Ls[i]);}if (q != null)for (int i = 0; i < 2; i++){Erase(p->s[i], q->Ls[i]);}p->setc(q, 1);p->push_up();}return splay();}inline Node* find_root() {Node *x;for (x = access(); x->push_down(), x->ch[0] != null; x = x->ch[0]);return x;}void make_root() {access()->flip();}void cut() {//把这个点的子树脱离出去access();ch[0]->fa = null;ch[0] = null;push_up();}void cut(Node *x) {if (this == x || find_root() != x->find_root())return;else {x->make_root();cut();}}void link(Node *x) {if (find_root() == x->find_root())return;else {make_root(); fa = x;}}};Node pool[N], *tail;Node *node[N];int n, q;struct Edge {int to, nex;}edge[N << 1];int head[N], edgenum;void add(int u, int v) {Edge E = { v, head[u] };edge[edgenum] = E;head[u] = edgenum++;}int col[N], val[N];void dfs(int u, int fa) {for (int i = head[u]; ~i; i = edge[i].nex) {int v = edge[i].to; if (v == fa)continue;node[v]->fa = node[u];dfs(v, u);for (int j = 0; j < 2; j++){node[u]->s[j].insert(node[v]->Ls[j]);}}node[u]->push_up();}int main() {while (cin >> n) {memset(head, -1, sizeof head); edgenum = 0;for (int i = 1, u, v; i < n; i++) {rd(u); rd(v);add(u, v);add(v, u);}tail = pool;null = tail++;null->clear(-1, -inf, 0); null->siz = 0;for (int i = 1; i <= n; i++) rd(col[i]);for (int i = 1; i <= n; i++) rd(val[i]);for (int i = 1; i <= n; i++){node[i] = tail++;node[i]->clear(col[i], val[i], i);}dfs(1, 1);rd(q); int u, v, w;while (q--) {rd(u); rd(v);if (0 == u) {node[v]->access();pt(max(node[v]->Rs[0], node[v]->Rs[1])); puts("");}else if (1 == u) {node[v]->access();node[v]->col ^= 1;node[v]->push_up();}else {rd(w);node[v]->access();node[v]->val = w;node[v]->push_up();}}}return 0;}