SPOJ_QTREE系列题解
Posted cwolf9
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QTREE4
#pragma comment(linker, "/STACK:102400000,102400000")
//#include<bits/stdc++.h>
#include <ctime>
#include <iostream>
#include <assert.h>
#include <vector>
#include <queue>
#include <cstdio>
#include <algorithm>
#include <cstring>
#define fi first
#define se second
#define endl '\n'
#define o2(x) (x)*(x)
#define BASE_MAX 31
#define mk make_pair
#define eb push_back
#define SZ(x) ((int)(x).size())
#define all(x) (x).begin(), (x).end()
#define clr(a, b) memset((a),(b),sizeof((a)))
#define iis std::ios::sync_with_stdio(false); cin.tie(0)
#define my_unique(x) sort(all(x)),x.erase(unique(all(x)),x.end())
using namespace std;
#pragma optimize("-O3")
typedef long long LL;
typedef unsigned long long uLL;
typedef pair<int, int> pii;
inline LL read()
LL x = 0;int f = 0;
char ch = getchar();
while (ch < '0' || ch > '9') f |= (ch == '-'), ch = getchar();
while (ch >= '0' && ch <= '9') x = (x << 3) + (x << 1) + ch - '0', ch = getchar();
return x = f ? -x : x;
inline void write(LL x, bool f)
if (x == 0) putchar('0'); if(f)putchar('\n');else putchar(' ');return;
if (x < 0) putchar('-');x = -x;
static char s[23];
int l = 0;
while (x != 0)s[l++] = x % 10 + 48, x /= 10;
while (l)putchar(s[--l]);
if(f)putchar('\n');else putchar(' ');
int lowbit(int x) return x & (-x);
template<class T>T big(const T &a1, const T &a2) return a1 > a2 ? a1 : a2;
template<class T>T sml(const T &a1, const T &a2) return a1 < a2 ? a1 : a2;
template<typename T, typename ...R>T big(const T &f, const R &...r) return big(f, big(r...));
template<typename T, typename ...R>T sml(const T &f, const R &...r) return sml(f, sml(r...));
void debug_out() cerr << '\n';
template<typename T, typename ...R>void debug_out(const T &f, const R &...r) cerr << f << " ";debug_out(r...);
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]: ", debug_out(__VA_ARGS__);
const LL INFLL = 0x3f3f3f3f3f3f3f3fLL;
const int HMOD[] = 1000000009, 1004535809;
const LL BASE[] = 1572872831, 1971536491;
const int mod = 1e9 + 7;//998244353
const int MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const int MXN = 2e5 + 7;
const int MXE = 4e5 + 7;
int n, m;
struct lp
int v, nex;
int w;
cw[MXE];
int tot, head[MXN];
namespace LCA
int dis[MXN], up[MXN][20], lens[MXN];
void dfs(int u, int ba, int d)
up[u][0] = ba; lens[u] = d;
for(int i = 1; i < 20; ++i) up[u][i] = up[up[u][i-1]][i-1];
for(int i = head[u], v; ~i; i = cw[i].nex)
v = cw[i].v;
if(v == ba) continue;
dis[v] = dis[u] + cw[i].w;
dfs(v, u, d + 1);
int lca(int x, int y)
if(lens[x] < lens[y]) swap(x, y);
for(int i = 19; i >= 0; --i)
if(lens[up[x][i]] >= lens[y])
x = up[x][i];
if(x == y) return x;
for(int i = 19; i >= 0; --i)
if(up[x][i] != up[y][i])
x = up[x][i], y = up[y][i];
return up[x][0];
int query(int i, int j)
return dis[i] + dis[j] - 2 * dis[lca(i, j)];
//namespace LCA
// int dis[MXN], up[MXN][20], lg[MXN], DEP[MXN];
// void dfs(int u, int ba)
// DEP[u] = DEP[ba] + 1;
// for(int i = head[u], v; ~i; i = cw[i].nex)
// v = cw[i].v;
// if(v == ba) continue;
// dis[v] = dis[u] + cw[i].w, up[v][0] = u;
// dfs(v, u);
//
//
// void init()
// for (int i = 2; i <= n; ++i) lg[i] = lg[i / 2] + 1;;
// dis[1] = 0;
// dfs(1, -1);
// for (int j = 1; j <= lg[n]; ++j)
// for (int i = 1; i <= n; ++i) up[i][j] = up[up[i][j - 1]][j - 1];
//
// int lca(int x, int y)
// if (DEP[x] > DEP[y]) swap(x, y);
// int k = DEP[y] - DEP[x];
// for (int i = 0; k; k = k / 2, ++i)
// if (k & 1) y = up[y][i];
// if (x == y) return x;
// k = DEP[x];
// for (int i = lg[k]; i >= 0; --i)
// if (up[x][i] != up[y][i]) x = up[x][i], y = up[y][i];
// return up[x][0];
//
// int query(int i, int j)
// return dis[i] + dis[j] - 2 * dis[lca(i, j)];
//
//
//namespace LCA
// int dis[MXN], up[MXN][20], lens[MXN];
// int cnt, dfn[MXN], en[MXN], LOG[MXN];
// void dfs(int u, int ba)
// lens[u] = lens[ba] + 1;
// dfn[++cnt] = u;
// en[u] = cnt;
// for(int i = head[u], v; ~i; i = cw[i].nex)
// v = cw[i].v;
// if(v == ba) continue;
// dis[v] = dis[u] + cw[i].w;
// dfs(v, u);
// dfn[++ cnt] = u;
//
//
// inline int cmp(int u, int v)
// return lens[u] < lens[v] ? u: v;
//
// void init()
// cnt = 0;
// dis[0] = lens[0] = 0;
// dfs(1, 0);
// LOG[1] = 0;
// for(int i = 2; i <= cnt; ++i) LOG[i] = LOG[i-1] + ((1<<(LOG[i-1]+1))==i);
// for(int i = 1; i <= cnt; ++i) up[i][0] = dfn[i];
// for(int j = 1; (1<<j) <= cnt; ++j)
// for(int i = 1; i + (1<<j) -1 <= cnt; ++i)
// up[i][j] = cmp(up[i][j-1], up[i+(1<<(j-1))][j-1]);
//
// inline int lca(int x, int y)
// int l = en[x], r = en[y];
// if(l > r) swap(l, r);
// int k = LOG[r - l + 1];
// return cmp(up[l][k], up[r-(1<<k)+1][k]);
//
// inline int query(int i, int j)
// return dis[i] + dis[j] - 2 * dis[lca(i, j)];
//
//
int siz[MXN], hvy, hvysiz, mxsz, vis[MXN];
int col[MXN], fa[MXN], dis[MXN][20];
int dep[MXN];
struct heap
priority_queue<int> A, B; // heap=A-B
void insert(int x) A.push(x);
void erase(int x) B.push(x);
inline int size() return A.size() - B.size();
inline int top()
if(size() <= 0) return -INF;
while (!B.empty() && A.top() == B.top()) A.pop(), B.pop();
return A.top();
inline void pop()
while (!B.empty() && A.top() == B.top()) A.pop(), B.pop();
A.pop();
inline int top2()
int t = top(), ret;
pop();
ret = top();
A.push(t);
return ret;
inline int mx()
if(size() < 2) return - INF;
int t = top(), ret;
pop();
ret = top();
A.push(t);
return ret + t;
disf[MXN], dison[MXN], ans;
inline void add_edge(int a, int b, int c)
cw[++ tot].v = b, cw[tot].nex = head[a], cw[tot].w = c;
head[a] = tot;
cw[++ tot].v = a, cw[tot].nex = head[b], cw[tot].w = c;
head[b] = tot;
inline int get_dis(int i, int j)
if(i == j) return 0;
if(dis[i][dep[i] - dep[j]]) return dis[i][dep[i] - dep[j]];
dis[i][dep[i] - dep[j]] = LCA::query(i, j);
return dis[i][dep[i] - dep[j]];
void dfs_pre(int u, int ba)
siz[u] = 1;
int mm = 0;
for(int i = head[u], v; ~i; i = cw[i].nex)
v = cw[i].v;
if(v == ba || vis[v]) continue;
dfs_pre(v, u);
siz[u] += siz[v];
mm = max(mm, siz[v]);
mm = max(mm, mxsz - siz[u]);
if(hvy == -1 || mm < hvysiz)
hvy = u;
hvysiz = mm;
void dfs_siz(int u, int ba)
siz[u] = 1;
for(int i = head[u], v; ~i; i = cw[i].nex)
v = cw[i].v;
if(v == ba || vis[v]) continue;
dfs_siz(v, u);
siz[u] += siz[v];
void dfs_dis(int u, int ba, int d, int rt)
disf[rt].insert(d);
for(int i = head[u], v; ~i; i = cw[i].nex)
v = cw[i].v;
if(v == ba || vis[v]) continue;
dfs_dis(v, u, d + cw[i].w, rt);
void dfs_get(int lstrt)
// debug(u, _n, hvy)
// int lstrt = u;
vis[lstrt] = 1;
assert(lstrt == hvy);
dfs_siz(lstrt, -1);
dison[lstrt].insert(0);//response itself
for(int i = head[lstrt], v; ~i; i = cw[i].nex)
v = cw[i].v;
if(vis[v]) continue;
hvy = -1;
hvysiz = mxsz = siz[v];
dfs_pre(v, lstrt);
dfs_dis(v, lstrt, cw[i].w, hvy);
fa[hvy] = lstrt;
dep[hvy] = dep[lstrt] + 1;
int tmp = disf[hvy].top();
if(tmp != - INF) dison[lstrt].insert(tmp);
dfs_get(hvy);
int tmp = dison[lstrt].mx();
if(tmp != - INF) ans.insert(tmp);
void change(int x, int open)
int preV = dison[x].mx(), nowV;
if(open) dison[x].erase(0);
else dison[x].insert(0);
nowV = dison[x].mx();
if(preV != nowV)
if(preV != -INF) ans.erase(preV);
if(nowV != -INF) ans.insert(nowV);
for(int u = x, ba; fa[u]; u = fa[u])
ba = fa[u];
// debug(x, i, fa[i])
int tmp = disf[u].top();
preV = dison[ba].mx();
if(open) disf[u].erase(get_dis(x, ba));
else disf[u].insert(get_dis(x, ba));
nowV = disf[u].top();
if(tmp != nowV)
if(tmp != -INF) dison[ba].erase(tmp);
if(nowV != - INF) dison[ba].insert(nowV);
nowV = dison[ba].mx();
if(preV != nowV)
if(preV != -INF) ans.erase(preV);
if(nowV != -INF) ans.insert(nowV);
int main()
#ifndef ONLINE_JUDGE
freopen("/home/cwolf9/CLionProjects/ccc/in.txt", "r", stdin);
//freopen("/home/cwolf9/CLionProjects/ccc/out.txt", "w", stdout);
#endif
n = read();
for(int i = 1; i <= n; ++i) head[i] = -1, col[i] = 0;
tot = -1;
for(int i = 1, a, b, c; i < n; ++i)
a = read(), b = read(), c = read();
add_edge(a, b, c);
// LCA::init();
LCA::dfs(1, 0, 0);
hvy = -1;
hvysiz = mxsz = n;
dfs_pre(1, -1);
dfs_get(hvy);
m = read();
// debug(m, get_dis(1, 3), dep[1], dep[3])
char op[3];
int x, cnt = n;
while(m --)
scanf("%s", op);
if(op[0] == 'A')
if(cnt == 0) printf("They have disappeared.\n");
else if(cnt == 1) printf("0\n");
else printf("%d\n", max(ans.top(), 0));
else
x = read();
if(col[x] == 0)
change(x, 1);
-- cnt;
else
change(x, 0);
++ cnt;
col[x] = !col[x];
#ifndef ONLINE_JUDGE
cout << "time cost:" << 1.0*clock()/CLOCKS_PER_SEC << "ms" << endl;
#endif
return 0;
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