【bzoj1146】[CTSC2008]网络管理Network 倍增LCA+dfs序+树状数组+主席树

#include <cstdio>
#include <algorithm>
#define N 80010
using namespace std;
int w[N] , head[N] , to[N << 1] , next[N << 1] , cnt , fa[N][18] , deep[N] , log[N] , lp[N] , rp[N] , num;
int ls[N * 200] , rs[N * 200] , si[N * 200] , root[N << 1] , tot , A[40] , B[40] , C[40] , D[40] , ta , tb , tc , td;
int v[N << 1] , tv , vk[N] , vx[N] , vy[N];
void add(int x , int y)
{
	to[++cnt] = y , next[cnt] = head[x] , head[x] = cnt;
}
void dfs(int x)
{
	int i;
	lp[x] = ++num;
	for(i = 1 ; (1 << i) <= deep[x] ; i ++ ) fa[x][i] = fa[fa[x][i - 1]][i - 1];
	for(i = head[x] ; i ; i = next[i])
		if(to[i] != fa[x][0])
			fa[to[i]][0] = x , deep[to[i]] = deep[x] + 1 , dfs(to[i]);
	rp[x] = ++num;
}
int lca(int x , int y)
{
	int i;
	if(deep[x] < deep[y]) swap(x , y);
	for(i = log[deep[x] - deep[y]] ; ~i ; i -- )
		if(deep[x] - deep[y] >= (1 << i))
			x = fa[x][i];
	if(x == y) return x;
	for(i = log[deep[x]] ; ~i ; i -- )
		if(deep[x] >= (1 << i) && fa[x][i] != fa[y][i])
			x = fa[x][i] , y = fa[y][i];
	return fa[x][0];
}
void update(int p , int a , int l , int r , int &x)
{
	if(!x) x = ++tot;
	si[x] += a;
	if(l == r) return;
	int mid = (l + r) >> 1;
	if(p <= mid) update(p , a , l , mid , ls[x]);
	else update(p , a , mid + 1 , r , rs[x]);
}
int query(int k , int l , int r)
{
	if(l == r) return l;
	int mid = (l + r) >> 1 , sum = 0 , i;
	for(i = 1 ; i <= ta ; i ++ ) sum += si[rs[A[i]]];
	for(i = 1 ; i <= tb ; i ++ ) sum += si[rs[B[i]]];
	for(i = 1 ; i <= tc ; i ++ ) sum -= si[rs[C[i]]];
	for(i = 1 ; i <= td ; i ++ ) sum -= si[rs[D[i]]];
	if(k <= sum)
	{
		for(i = 1 ; i <= ta ; i ++ ) A[i] = rs[A[i]];
		for(i = 1 ; i <= tb ; i ++ ) B[i] = rs[B[i]];
		for(i = 1 ; i <= tc ; i ++ ) C[i] = rs[C[i]];
		for(i = 1 ; i <= td ; i ++ ) D[i] = rs[D[i]];
		return query(k , mid + 1 , r);
	}
	else
	{
		for(i = 1 ; i <= ta ; i ++ ) A[i] = ls[A[i]];
		for(i = 1 ; i <= tb ; i ++ ) B[i] = ls[B[i]];
		for(i = 1 ; i <= tc ; i ++ ) C[i] = ls[C[i]];
		for(i = 1 ; i <= td ; i ++ ) D[i] = ls[D[i]];
		return query(k - sum , l , mid);
	}
}
int main()
{
	int n , q , i , j , x , y , f;
	scanf("%d%d" , &n , &q);
	for(i = 1 ; i <= n ; i ++ ) scanf("%d" , &w[i]) , v[++tv] = w[i];
	for(i = 2 ; i <= n ; i ++ ) scanf("%d%d" , &x , &y) , add(x , y) , add(y , x) , log[i] = log[i >> 1] + 1;
	dfs(1);
	for(i = 1 ; i <= q ; i ++ )
	{
		scanf("%d%d%d" , &vk[i] , &vx[i] , &vy[i]);
		if(!vk[i]) v[++tv] = vy[i];
	}
	sort(v + 1 , v + tv + 1);
	for(tv = 0 , i = 1 ; i <= n + q ; i ++ )
		if(v[i] != v[i - 1])
			v[++tv] = v[i];
	for(i = 1 ; i <= n ; i ++ )
	{
		w[i] = lower_bound(v + 1 , v + tv + 1 , w[i]) - v;
		for(j = lp[i] ; j <= num ; j += j & -j) update(w[i] , 1 , 1 , tv , root[j]);
		for(j = rp[i] ; j <= num ; j += j & -j) update(w[i] , -1 , 1 , tv , root[j]);
	}
	for(i = 1 ; i <= q ; i ++ )
	{
		if(vk[i])
		{
			f = lca(vx[i] , vy[i]);
			if(deep[vx[i]] + deep[vy[i]] - 2 * deep[f] + 1 < vk[i]) puts("invalid request!");
			else
			{
				ta = tb = tc = td = 0;
				for(j = lp[vx[i]] ; j ; j -= j & -j) A[++ta] = root[j];
				for(j = lp[vy[i]] ; j ; j -= j & -j) B[++tb] = root[j];
				for(j = lp[f] ; j ; j -= j & -j) C[++tc] = root[j];
				for(j = lp[fa[f][0]] ; j ; j -= j & -j) D[++td] = root[j];
				printf("%d\n" , v[query(vk[i] , 1 , tv)]);
			}
		}
		else
		{
			vy[i] = lower_bound(v + 1 , v + tv + 1 , vy[i]) - v;
			for(j = lp[vx[i]] ; j <= num ; j += j & -j) update(w[vx[i]] , -1 , 1 , tv , root[j]) , update(vy[i] , 1 , 1 , tv , root[j]);
			for(j = rp[vx[i]] ; j <= num ; j += j & -j) update(w[vx[i]] , 1 , 1 , tv , root[j]) , update(vy[i] , -1 , 1 , tv , root[j]);
			w[vx[i]] = vy[i];
		}
	}
	return 0;
}