【bzoj3362/3363/3364/3365】[Usaco2004 Feb]树上问题杂烩 并查集/树形dp/LCA/树的点分治

#include <cstdio>
#include <cmath>
#include <algorithm>
#define N 40010
using namespace std;
struct data
{
	int x , y , p , pos;
}q[10010];
int a[N] , b[N] , cx[N] , cy[N] , f[N] , dx[N] , dy[N] , ans[10010];
char str[5];
bool cmp(data a , data b)
{
	return a.p < b.p;
}
int find(int x)
{
	if(x == f[x]) return x;
	int t = f[x];
	f[x] = find(t);
	dx[x] += dx[t];
	dy[x] += dy[t];
	return f[x];
}
int main()
{
	int n , i , t , m , ta , tb;
	scanf("%d%*d" , &n);
	for(i = 1 ; i < n ; i ++ )
	{
		scanf("%d%d%d%s" , &a[i] , &b[i] , &t , str);
		if(str[0] == ‘E‘) cx[i] = t;
		if(str[0] == ‘S‘) cy[i] = t;
		if(str[0] == ‘W‘) cx[i] = -t;
		if(str[0] == ‘N‘) cy[i] = -t;
	}
	scanf("%d" , &m);
	for(i = 1 ; i <= m ; i ++ ) scanf("%d%d%d" , &q[i].x , &q[i].y , &q[i].p) , q[i].pos = i;;
	sort(q + 1 , q + m + 1 , cmp);
	for(i = 1 ; i <= n ; i ++ ) f[i] = i;
	for(t = i = 1 ; i <= m ; i ++ )
	{
		while(t <= q[i].p)
		{
			ta = find(a[t]) , tb = find(b[t]);
			if(ta != tb) f[ta] = tb , dx[ta] = dx[b[t]] + cx[t] - dx[a[t]] , dy[ta] = dy[b[t]] + cy[t] - dy[a[t]];
			t ++ ;
		}
		ta = find(q[i].x) , tb = find(q[i].y);
		ans[q[i].pos] = (ta == tb ? abs(dx[q[i].x] - dx[q[i].y]) + abs(dy[q[i].x] - dy[q[i].y]) : -1);
	}
	for(i = 1 ; i <= m ; i ++ ) printf("%d\n" , ans[i]);
	return 0;
}

#include <cstdio>
#include <cstring>
#define N 40010
int head[N] , to[N << 1] , len[N << 1] , next[N << 1] , cnt , deep[N];
void add(int x , int y , int z)
{
	to[++cnt] = y , len[cnt] = z , next[cnt] = head[x] , head[x] = cnt;
}
void dfs(int x , int fa)
{
	int i;
	for(i = head[x] ; i ; i = next[i])
		if(to[i] != fa)
			deep[to[i]] = deep[x] + len[i] , dfs(to[i] , x);
}
int main()
{
	int n , i , x , y , z , k;
	scanf("%d%*d" , &n);
	for(i = 1 ; i < n ; i ++ ) scanf("%d%d%d%*s" , &x , &y , &z) , add(x , y , z) , add(y , x , z);
	dfs(1 , 0);
	for(k = 0 , i = 1 ; i <= n ; i ++ ) if(deep[i] > deep[k]) k = i;
	memset(deep , 0 , sizeof(deep)) , dfs(k , 0);
	for(k = 0 , i = 1 ; i <= n ; i ++ ) if(deep[i] > k) k = deep[i];
	printf("%d\n" , k);
	return 0;
}

#include <cstdio>
#include <algorithm>
#define N 40010
using namespace std;
int head[N] , to[N << 1] , len[N << 1] , next[N << 1] , cnt , fa[N][18] , deep[N] , dis[N][18] , log[N];
void add(int x , int y , int z)
{
	to[++cnt] = y , len[cnt] = z , next[cnt] = head[x] , head[x] = cnt;
}
void dfs(int x)
{
	int i;
	for(i = 1 ; i <= log[deep[x]] ; i ++ )
		fa[x][i] = fa[fa[x][i - 1]][i - 1] , dis[x][i] = dis[x][i - 1] + dis[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 , dis[to[i]][0] = len[i] , deep[to[i]] = deep[x] + 1 , dfs(to[i]);
}
int query(int x , int y)
{
	int i , ans = 0;
	if(deep[x] <= deep[y]) swap(x , y);
	for(i = log[deep[x] - deep[y]] ; ~i ; i -- )
		if(deep[x] - (1 << i) >= deep[y])
			ans += dis[x][i] , x = fa[x][i];
	if(x == y) return ans;
	for(i = log[deep[x]] ; ~i ; i -- )
		if(fa[x][i] != fa[y][i])
			ans += dis[x][i] + dis[y][i] , x = fa[x][i] , y = fa[y][i];
	return ans + dis[x][0] + dis[y][0];
}
int main()
{
	int n , i , x , y , z , k;
	scanf("%d%*d" , &n);
	for(i = 1 ; i < n ; i ++ ) scanf("%d%d%d%*s" , &x , &y , &z) , add(x , y , z) , add(y , x , z);
	for(i = 2 ; i <= n ; i ++ ) log[i] = log[i >> 1] + 1;
	dfs(1);
	scanf("%d" , &k);
	while(k -- ) scanf("%d%d" , &x , &y) , printf("%d\n" , query(x , y));
	return 0;
}

#include <cstdio>
#include <cstring>
#include <algorithm>
#define N 40010
using namespace std;
int m , head[N] , to[N << 1] , len[N << 1] , next[N << 1] , cnt , si[N] , deep[N] , root , vis[N] , f[N] , sn , d[N] , tot , ans;
void add(int x , int y , int z)
{
	to[++cnt] = y , len[cnt] = z , next[cnt] = head[x] , head[x] = cnt;
}
void getroot(int x , int fa)
{
	f[x] = 0 , si[x] = 1;
	int i;
	for(i = head[x] ; i ; i = next[i])
		if(to[i] != fa && !vis[to[i]])
			getroot(to[i] , x) , si[x] += si[to[i]] , f[x] = max(f[x] , si[to[i]]);
	f[x] = max(f[x] , sn - si[x]);
	if(f[root] > f[x]) root = x;
}
void getdeep(int x , int fa)
{
	d[++tot] = deep[x];
	int i;
	for(i = head[x] ; i ; i = next[i])
		if(to[i] != fa && !vis[to[i]])
			deep[to[i]] = deep[x] + len[i] , getdeep(to[i] , x);
}
int calc(int x)
{
	tot = 0 , getdeep(x , 0) , sort(d + 1 , d + tot + 1);
	int i = 1 , j = tot , sum = 0;
	while(i < j)
	{
		if(d[i] + d[j] <= m) sum += j - i , i ++ ;
		else j -- ;
	}
	return sum;
}
void dfs(int x)
{
	deep[x] = 0 , vis[x] = 1 , ans += calc(x);
	int i;
	for(i = head[x] ; i ; i = next[i])
		if(!vis[to[i]])
			deep[to[i]] = len[i] , ans -= calc(to[i]) , sn = si[to[i]] , root = 0 , getroot(to[i] , 0) , dfs(root);
}
int main()
{
	int n , i , x , y , z;
	scanf("%d%*d" , &n);
	for(i = 1 ; i < n ; i ++ )
		scanf("%d%d%d%*s" , &x , &y , &z) , add(x , y , z) , add(y , x , z);
	scanf("%d" , &m);
	f[0] = 0x7fffffff , sn = n;
	getroot(1 , 0) , dfs(root);
	printf("%d\n" , ans);
	return 0;
}