# 【題解】CSES 1136 Counting Paths

```#include <iostream>
#include <vector>
using namespace std;

int n, q, a, b, p[200005][20], d[200005], dp[200005];
vector <int> v[200005];

void dfs(int x, int pre){
for (auto i:v[x]){
if (i == pre) continue;
p[i][0] = x;
d[i] = d[x]+1;
dfs(i, x);
}
}
int lca(int a, int b){
int x = d[a], y = d[b];
if (x > y){
swap(a, b);
swap(x, y);
}
y -= x;
for (int i = 0; i < 20; i++){
if (y & (1<<i)){
b = p[b][i];
}
}
if (a == b) return a;
for (int i = 19; i >= 0; i--){
if (p[a][i] != p[b][i]){
a = p[a][i];
b = p[b][i];
}
}
return p[a][0];
}
void dfs2(int x, int pre){
for (auto i:v[x]){
if (i == pre) continue;
dfs2(i, x);
dp[x] += dp[i];
}
}
int main() {
cin >> n >> q;
for (int i = 2; i <= n; i++){
cin >> a >> b;
v[a].push_back(b);
v[b].push_back(a);
}
dfs(1, 0);
for (int i = 1; i < 20; i++){
for (int j = 1; j <= n; j++){
p[j][i] = p[p[j][i-1]][i-1];
}
}
while (q--){
cin >> a >> b;
dp[a]++;
dp[b]++;
dp[p[lca(a, b)][0]]--;
dp[lca(a, b)]--;
}
dfs2(1, 0);
for (int i = 1; i <= n; i++){
cout << dp[i] << " ";
}
}
```