【BZOJ1095】[ZJOI2007]Hide 捉迷藏【動態樹分治】__分治

【題目連結】

學習了一發可刪堆。

找重心那裡忘了寫!del[g[i].v]，RE無數發。

/* Pigonometry */#include <cstdio>#include <cstring>#include <algorithm>#include <queue>using namespace std;const int maxn = 100005, maxm = maxn << 1, maxk = 21, inf = 0x3f3f3f3f;int n, head[maxn], cnt;int root, clo, tot, bin[maxk], lg[maxm];int size[maxn], depth[maxn], sm[maxn], pre[maxn], st[maxk][maxm], dfn[maxn], del[maxn], col[maxn];struct _heap {priority_queue<int> A, B;void update() {for(; B.size() && A.top() == B.top(); A.pop(), B.pop());}void push(int x) {A.push(x);}void pop() {update();A.pop();}void erase(int x) {B.push(x);}int size() {return A.size() - B.size();}int first() {update();return A.size() ? A.top() : 0;}int second() {if(size() < 2) return 0;int x = first(); pop();int y = first(); push(x);return y;}} A, B[maxn], C[maxn];struct _edge {int v, next;} g[maxn << 1];inline int iread() {int f = 1, x = 0; char ch = getchar();for(; ch < '0' || ch > '9'; ch = getchar()) f = ch == '-' ? -1 : 1;for(; ch >= '0' && ch <= '9'; ch = getchar()) x = x * 10 + ch - '0';return f * x;}inline void add(int u, int v) {g[cnt] = (_edge){v, head[u]};head[u] = cnt++;}inline void dfs(int x, int f) {st[0][++clo] = depth[x];dfn[x] = clo;for(int i = head[x]; ~i; i = g[i].next) if(g[i].v ^ f) {depth[g[i].v] = depth[x] + 1;dfs(g[i].v, x);st[0][++clo] = depth[x];}}inline int getlca(int u, int v) {u = dfn[u]; v = dfn[v];if(u > v) swap(u, v);int t = lg[v - u + 1];return min(st[t][u], st[t][v - bin[t] + 1]);}inline int dis(int u, int v) {return depth[u] + depth[v] - (getlca(u, v) << 1);}inline void find(int x, int f) {size[x] = 1; sm[x] = 0;for(int i = head[x]; ~i; i = g[i].next) if(g[i].v ^ f && !del[g[i].v]) {find(g[i].v, x);size[x] += size[g[i].v];sm[x] = max(sm[x], size[g[i].v]);}sm[x] = max(sm[x], tot - size[x]);if(sm[x] < sm[root]) root = x;}inline void divide(int x, int f) {pre[x] = f; del[x] = 1;for(int i = head[x]; ~i; i = g[i].next) if(g[i].v ^ f && !del[g[i].v]) {root = 0; tot = size[g[i].v];find(g[i].v, x); divide(root, x);}}inline void turnoff(int x, int f) {if(x == f) {B[x].push(0);if(B[x].size() == 2) A.push(B[x].first());}if(!pre[f]) return;int p = pre[f], d = dis(x, p), tmp = C[f].first();C[f].push(d);if(d > tmp) {int mx = B[p].first() + B[p].second(), sz = B[p].size();B[p].push(d);if(tmp) B[p].erase(tmp);int now = B[p].first() + B[p].second();if(now > mx) {if(sz >= 2) A.erase(mx);if(B[p].size() >= 2) A.push(now);}}turnoff(x, p);}inline void turnon(int x, int f) {if(x == f) {if(B[x].size() == 2) A.erase(B[x].first());B[x].erase(0);}if(!pre[f]) return;int p = pre[f], d = dis(x, p), tmp = C[f].first();C[f].erase(d);if(d == tmp) {int mx = B[p].first() + B[p].second(), sz = B[p].size();B[p].erase(d);if(C[f].first()) B[p].push(C[f].first());int now = B[p].first() + B[p].second();if(now < mx) {if(sz >= 2) A.erase(mx);if(B[p].size() >= 2) A.push(now);}}turnon(x, p);}int main() {n = iread();for(int i = 0; i <= n; i++) head[i] = -1; cnt = 0;bin[0] = 1;for(int i = 1; i < maxk; i++) bin[i] = bin[i - 1] << 1;lg[0] = -1;for(int i = 1; i < maxm; i++) lg[i] = lg[i >> 1] + 1;for(int i = 1; i < n; i++) {int u = iread(), v = iread();add(u, v); add(v, u);}dfs(1, 0);for(int j = 1; j < maxk; j++) for(int i = 1; i <= clo; i++) if(i + bin[j] - 1 <= clo)st[j][i] = min(st[j - 1][i], st[j - 1][i + bin[j - 1]]);sm[0] = inf; root = 0; tot = n;find(1, 0); divide(root, 0);for(int i = 1; i <= n; i++) C[i].push(0), col[i] = 1;for(int i = 1; i <= n; i++) turnoff(i, i);int node = n;for(int T = iread(); T; T--) {char ch = getchar(); for(; ch != 'C' && ch != 'G'; ch = getchar());if(ch == 'G') {if(node <= 1) printf("%d\n", node - 1);else printf("%d\n", A.first());}else if(ch == 'C') {int u = iread();if(col[u] == 1) node--, turnon(u, u);else node++, turnoff(u, u);col[u] ^= 1;}}return 0;}