CF191C——Fools and Roads（树上边差分+LCA）

#pragma GCC optimize(2)
#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll, ll>PLL;
typedef pair<int, int>PII;
typedef pair<double, double>PDD;
#define I_int ll
inline ll read()
{
    ll x = 0, f = 1;
    char ch = getchar();
    while(ch < '0' || ch > '9')
    {
        if(ch == '-')f = -1;
        ch = getchar();
    }
    while(ch >= '0' && ch <= '9')
    {
        x = x * 10 + ch - '0';
        ch = getchar();
    }
    return x * f;
}
#define read read()
#define closeSync ios::sync_with_stdio(0);cin.tie(0);cout.tie(0)
#define multiCase int T;cin>>T;for(int t=1;t<=T;t++)
#define rep(i,a,b) for(int i=(a);i<=(b);i++)
#define repp(i,a,b) for(int i=(a);i<(b);i++)
#define per(i,a,b) for(int i=(a);i>=(b);i--)
#define perr(i,a,b) for(int i=(a);i>(b);i--)
ll ksm(ll a, ll b, ll p)
{
    ll res = 1;
    while(b)
    {
        if(b & 1)res = res * a % p;
        a = a * a % p;
        b >>= 1;
    }
    return res;
}
const int inf = 0x3f3f3f3f;
#define PI acos(-1)
const double eps = 1e-8;
const int maxn =2e5+7;
struct LCA
{
    int fa[maxn][25], dep[maxn];
    int e[maxn],ne[maxn],m;
    int h[maxn], idx = 0,n,root;
    void add(int a,int b){
      e[idx]=b,ne[idx]=h[a],h[a]=idx++;///链式前向星存图
  }
    void init()
    {
        memset(h, -1, sizeof h);
        idx = 0;
        /*for(int i=1;i<n;i++){
          int u=read,v=read;
          add(u,v);add(v,u);
        }*/
    }
    void bfs(int root)
    {
        queue<int>q;
        memset(dep, 0x3f, sizeof dep);
        dep[0] = 0; ///特殊处理
        dep[root] = 1;
        q.push(root);
        while(!q.empty())
        {
            int t = q.front();
            q.pop();
            for(int i = h[t]; ~i; i = ne[i])
            {
                int j = e[i];
                if(dep[j] > dep[t] + 1)
                {
                    dep[j] = dep[t] + 1;
                    q.push(j);
                    fa[j][0] = t; ///预处理fa数组
                    for(int k = 1; k <= 20; k++)
                        fa[j][k] = fa[fa[j][k - 1]][k - 1];
                }
            }
        }
    }
    int lca(int a, int b)
    {
        if(dep[a] < dep[b]) swap(a, b);
        for(int k = 20; k >= 0; k--)
            if(dep[fa[a][k]] >= dep[b]) a = fa[a][k]; ///使a,b跳到同一层
        if(a == b) return a;
        for(int k = 20; k >= 0; k--)
            if(fa[a][k] != fa[b][k]) a = fa[a][k], b = fa[b][k];
        return fa[a][0];
    }
};
LCA l;
int d[maxn];
PII pos[maxn];
void dfs(int u,int fa){
  for(int i=l.h[u];~i;i=l.ne[i]){
    int j=l.e[i];
    if(j==fa) continue;
    dfs(j,u);
    d[u]+=d[j];
  }
}
int main(){
  l.init();
  l.n=read;
  for(int i=1;i<l.n;i++){
    int u=read,v=read;
    pos[i]={u,v};
    l.add(u,v);l.add(v,u);
  }
  l.bfs(1);
  int m=read;
  for(int i=1;i<=m;i++){
    int u=read,v=read;
    d[u]++;d[v]++;d[l.lca(u,v)]-=2;
  }
  dfs(1,0);
  for(int i=1;i<l.n;i++){
    int d1=l.dep[pos[i].first],d2=l.dep[pos[i].second];
    if(d1>d2) cout<<d[pos[i].first]<<" ";
    else  cout<<d[pos[i].second]<<" ";
  }
  return 0;
}