【BZOJ1103】[POI2007]大都市meg【树链剖分】【线段树】【或 树状数组 + dfs序】

/* Pigonometry */
#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;

const int maxn = 250005;

int n, head[maxn], cnt;

struct _edge {
int v, next;
} g[maxn];

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++;
}

int pre[maxn], son[maxn], size[maxn], dfn[maxn], clo, top[maxn];
int tr[maxn << 2];

inline void dfs(int x) {
size[x] = 1; son[x] = 0;
for(int i = head[x]; ~i; i = g[i].next) if(g[i].v ^ pre[x]) {
pre[g[i].v] = x;
dfs(g[i].v);
size[x] += size[g[i].v];
if(size[g[i].v] > size[son[x]]) son[x] = g[i].v;
}
}

inline void dfs2(int x, int tp) {
top[x] = tp; dfn[x] = ++clo;
if(son[x]) dfs2(son[x], tp);
for(int i = head[x]; ~i; i = g[i].next) if(g[i].v ^ pre[x] && g[i].v ^ son[x])
dfs2(g[i].v, g[i].v);
}

inline void pushup(int p) {
tr[p] = tr[p << 1] + tr[p << 1 | 1];
}

inline void build(int p, int l, int r) {
if(l == r) {
if(l == 1) tr[p] = 0;
else tr[p] = 1;
return;
}
int mid = l + r >> 1;
build(p << 1, l, mid); build(p << 1 | 1, mid + 1, r);
pushup(p);
}

inline int query(int p, int l, int r, int x, int y) {
if(x <= l && r <= y) return tr[p];
int mid = l + r >> 1, res = 0;
if(x <= mid) res += query(p << 1, l, mid, x, y);
if(y > mid) res += query(p << 1 | 1, mid + 1, r, x, y);
return res;
}

inline int querychain(int u) {
int res = 0;
for(; u; u = pre[top[u]])
res += query(1, 1, clo, dfn[top[u]], dfn[u]);
return res;
}

inline void change(int p, int l, int r, int x, int c) {
if(l == r && r == x) {
tr[p] = c;
return;
}
int mid = l + r >> 1;
if(x <= mid) change(p << 1, l, mid, x, c);
else change(p << 1 | 1, mid + 1, r, x, c);
pushup(p);
}

int main() {
n = iread();
for(int i = 1; i <= n; i++) head[i] = -1; cnt = 0;

for(int i = 1; i < n; i++) {
int u = iread(), v = iread();
if(u > v) swap(u, v);
add(u, v);
}
dfs(1); dfs2(1, 1);
build(1, 1, clo);
for(int T = iread(); T; ) {
char ch = getchar(); for(; ch != 'W' && ch != 'A'; ch = getchar());
if(ch == 'W') {
T--;
int u = iread();
printf("%d\n", querychain(u));
}
else if(ch == 'A') {
int u = iread(), v = iread();
if(u > v) swap(u, v);
change(1, 1, clo, dfn[v], 0);
}
}
return 0;
}

/* Pigonometry */
#include <cstdio>
#include <cstring>
#include <algorithm>

using namespace std;

const int maxn = 250005, maxm = maxn << 1;

int n, m, head[maxn], cnt, st[maxn], ed[maxn], clo, pre[maxn], tr[maxm];

struct _edge {
int v, next;
} g[maxn];

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 addedge(int u, int v) {
g[cnt] = (_edge){v, head[u]};
head[u] = cnt++;
}

inline void add(int x, int c) {
for(; x <= m; x += x & -x) tr[x] += c;
}

inline int sum(int x) {
int res = 0;
for(; x; x -= x & -x) res += tr[x];
return res;
}

inline void dfs(int x) {
st[x] = ++clo;
add(clo, 1);
for(int i = head[x]; ~i; i = g[i].next) if(g[i].v ^ pre[x]) {
pre[g[i].v] = x;
dfs(g[i].v);
}
ed[x] = ++clo;
add(clo, -1);
}

int main() {
n = iread(); m = n << 1;
for(int i = 1; i <= n; i++) head[i] = -1; cnt = 0;

for(int i = 1; i < n; i++) {
int u = iread(), v = iread();
if(u > v) swap(u, v);
addedge(u, v);
}
dfs(1);
for(int T = iread(); T; ) {
char ch = getchar(); for(; ch != 'W' && ch != 'A'; ch = getchar());
if(ch == 'W') {
T--;
int u = iread();
printf("%d\n", sum(st[u]) - 1);
}
else if(ch == 'A') {
int u = iread(), v = iread();
if(u > v) swap(u, v);
add(st[v], -1); add(ed[v], 1);
}
}
return 0;
}