This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <iostream>
#include <algorithm>
#include <vector>
using namespace std;
#define endl '\n'
const int MAXN=1e5+10;
const int BUCK=450;
struct Query {
    int l, r;
    int ind;
    bool friend operator < (Query a, Query b) {
        return a.r>b.r;
    }
};
Query que[MAXN];
vector <int> v[MAXN];
vector <int> arr, isl;
int c[MAXN];
int fe[MAXN], le[MAXN], in[MAXN], dep[MAXN];
int sp[2*MAXN][20], stepen[2*MAXN];
int n, m, q, cnt;
bool cmpi(int a, int b) {
    return in[a]<in[b];
}
void dfs(int x, int p) {
    in[x]=cnt;
    cnt++;
    fe[x]=arr.size();
    for (auto i:v[x]) {
        if (i==p) continue;
        arr.push_back(x);
        dep[i]=dep[x]+1;
        dfs(i,x);
    }
    le[x]=arr.size();
    arr.push_back(x);
}
void sparce_table() {
    int kn=arr.size();
    for (int i=0;i<kn;i++) sp[i][0]=arr[i];
    for (int i=1;(1<<i)<=kn;i++) {
        for (int j=0;j+(1<<i)-1<kn;j++) {
            int i1, i2;
            i1=sp[j][i-1];
            i2=sp[j + (1 << (i-1))][i-1];
            if (dep[i1]<dep[i2]) sp[j][i]=i1;
            else sp[j][i]=i2;
        }
    }
    int st=0;
    for (int i=1;i<=kn;i++) {
        if ((1 << (st+1))<i) st++;
        stepen[i]=st;
    }
}
int lca(int l, int r) {
    int st=stepen[r-l+1];
    int i1, i2;
    i1=sp[l][st];
    i2=sp[r - (1<<st)+1][st];
    if (dep[i1]<dep[i2]) return i1;
    return i2;
}
int getdist(int a, int b) {
    if (in[a]>in[b]) swap(a,b);
    return dep[a]+dep[b]-2*dep[lca(fe[a],fe[b])];
}
int main () {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    int a, b;
    cin >> n >> m >> q;
    for (int i=0;i<n-1;i++) {
        cin >> a >> b;
        v[a].push_back(b);
        v[b].push_back(a);
    }
    cnt=1;
    dfs(1,-1);
    sparce_table();
    for (int i=1;i<=m;i++) cin >> c[i];
    int ans;
    for (int i=0;i<q;i++) {
        cin >> que[i].l >> que[i].r;
        if (!isl.empty()) isl.clear();
        for (int j=que[i].l;j<=que[i].r;j++) isl.push_back(c[j]);
        sort(isl.begin(),isl.end(),cmpi);
        ans=0;
        for (int j=1;j<isl.size();j++) ans+=getdist(isl[j-1],isl[j]);
        if (isl.size()>1) ans+=getdist(isl[0],isl.back());
        cout << ans/2+1 << endl;
        que[i].ind=i;
    }
    return 0;
}
Compilation message (stderr)
tourism.cpp: In function 'int main()':
tourism.cpp:89:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   89 |         for (int j=1;j<isl.size();j++) ans+=getdist(isl[j-1],isl[j]);
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