LYDSY 1036_LCT
题目大意
暂无
题目解法
暂无
RTFC
#include <cctype>
#include <cstdio>
const int inf = 0x3f3f3f3f;
inline void read(int &x)
{
int ch = x = 0, flag = 1;
while (!isdigit(ch = getchar()))
if (ch == '-') flag = -1;
for (; isdigit(ch); ch = getchar()) x = x * 10 + ch - '0';
x *= flag;
}
template <typename T>
inline void swap(T &x, T &y)
{
T t = x;
x = y;
y = t;
}
template <typename T>
inline T max(const T &a, const T &b) { return a > b ? a : b; }
struct node
{
int val, sum, max;
node *fa, *ch[2];
bool rev;
inline int dir() { return (this == 0 || fa == 0) ? -1 : this == fa->ch[1]; }
bool isRoot() { return fa == 0 || (fa->ch[0] != this && fa->ch[1] != this); }
int getsum() { return this == 0 ? 0 : sum; }
int getmax() { return this == 0 ? -inf : max; }
} T[30050];
inline void push_down(node *x)
{
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_rec(node *x)
{
if (!x->isRoot()) push_down_rec(x->fa);
push_down(x);
}
inline void update(node *x)
{
if (x == 0) return;
x->sum = x->ch[0]->getsum() + x->val + x->ch[1]->getsum();
x->max = max(x->val, max(x->ch[0]->getmax(), x->ch[1]->getmax()));
}
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 (!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;
update(f), update(x);
}
inline void splay(node *x)
{
push_down_rec(x);
for (; !x->isRoot(); liftup(x))
if (!x->fa->isRoot())
liftup(x->dir() ^ x->fa->dir() ? x : x->fa);
update(x);
}
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];
return splay(x), 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;
}
inline node *Select(node *x, node *y)
{
return makeRoot(x), findRoot(y);
}
inline void Change(node *x, int v)
{
access(x), splay(x);
x->val = v;
update(x);
}
int main()
{
int n, m;
read(n);
{
static int u[30050], v[30050];
for (int i = 1; i < n; i++) read(u[i]), read(v[i]);
for (int i = 0; i < n; i++) read(T[i + 1].val), update(&T[i + 1]);
for (int i = 1; i < n; i++) Link(&T[u[i]], &T[v[i]]);
}
int u, v;
char op[10];
read(m);
while (m--)
{
scanf("%s", op);
if (op[1] == 'M') //QMAX
read(u), read(v), printf("%d\n", Select(&T[u], &T[v])->max);
if (op[1] == 'S') //QSUM
read(u), read(v), printf("%d\n", Select(&T[u], &T[v])->sum);
if (op[1] == 'H') //CHANGE
read(u), read(v), Change(&T[u], v);
}
return 0;
}