Language: C++

#include <iostream>
#include <sstream>
#include <string>
#include <algorithm>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <cmath>
#include <cassert>

using namespace std;

#define FOR(i,k,n) for(int i=(k); i<(int)(n); ++i)
#define REP(i,n) FOR(i,0,n)
#define FORIT(i,c) for(__typeof((c).begin())i=(c).begin();i!=(c).end();++i)

template<class T> void debug(T begin, T end){ for(T i = begin; i != end; ++i) cerr<<*i<<" "; cerr<<endl; }
inline bool valid(int x, int y, int W, int H){ return (x >= 0 && y >= 0 && x < W && y < H); }

typedef long long ll;
const int INF = 100000000;
const double EPS = 1e-8;
const int MOD = 1000000007;
int dx[8] = {1, 0, -1, 0, 1, -1, -1, 1};
int dy[8] = {0, 1, 0, -1, 1, 1, -1, -1};
struct Edge{
  int u, v;
  ll c;
  Edge(int u, int v, ll c) :
    u(u), v(v), c(c) {}
  bool operator < (const Edge& e) const {
    return c > e.c;
  }
};
typedef vector<Edge> Node;
typedef vector<Node> Graph;
void dijkstra(vector<ll>& dist, Graph& G, int s){
  int N = G.size();
  dist = vector<ll>(N, -1);
  priority_queue<Edge> que;
  que.push(Edge(-1, s, 0));
  dist[s] = 0;
  while(!que.empty()){
    Edge e = que.top(); que.pop();
    if(dist[e.v] < e.c) continue;
    REP(i, G[e.v].size()){
      Edge f = G[e.v][i];
      if(dist[f.v] == -1 || dist[f.v] > e.c + f.c){
        dist[f.v] = e.c + f.c;
        que.push(Edge(f.u, f.v, e.c + f.c));
      }
    }
  }
}

struct RangeTree{
  static const int ST_SIZE = (1<<20) - 1;
  vector<ll> dat[ST_SIZE];
  void init(int k, int l, int r, vector<ll>& v){
    if(r - l == 1){
      dat[k].push_back(v[l]);
    }else{
      int lch = k * 2 + 1, rch = k * 2 + 2;
      init(lch, l, (l + r) / 2, v);
      init(rch, (l + r) / 2, r, v);

      dat[k].resize(r - l);
      merge(dat[lch].begin(), dat[lch].end(), dat[rch].begin(), dat[rch].end(), dat[k].begin());
    }
  }
  int query(int i, int j, ll x, int k, int l, int r){
    if(j <= l || r <= i) return 0;
    if(i <= l && r <= j){
      return upper_bound(dat[k].begin(), dat[k].end(), x) - dat[k].begin();
    }else{
      int lc = query(i, j, x, 2 * k + 1, l, (l + r) / 2);
      int rc = query(i, j, x, 2 * k + 2, (l + r) / 2, r);
      return lc + rc;
    }
  }
};



int main(){
  int N, M;
  while(cin>>N>>M && N){
    Graph G(N);
    REP(i, M){
      int a, b, c;
      cin>>a>>b>>c;
      G[a].push_back(Edge(a, b, c));
      G[b].push_back(Edge(b, a, c));
    }
    vector<ll> dist, rdist;
    dijkstra(dist, G, 0);
    dijkstra(rdist, G, N - 1);
    debug(dist.begin(), dist.end());
    debug(rdist.begin(), rdist.end());

    vector<pair<ll, ll> > ps(N);
    REP(i, N){
      ps[i] = make_pair(dist[i], -rdist[i]);
    }
    sort(ps.begin(), ps.end());
    REP(i, N) {
      dist[i] = ps[i].first;
      rdist[i] = ps[i].second;
    }
    RangeTree tree;
    //tree.init(0, 0, N, rdist);

    int Q; cin>>Q;
    REP(i, Q){
      ll fs, fg;
      cin>>fs>>fg;
      int e = upper_bound(dist.begin(), dist.end(), fs) - dist.begin();
      //int ans = tree.query(0, e, -fg, 0, 0, N);
      cout<<ans<<endl;
    }
  }
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:124:13: error: 'ans' was not declared in this scope; did you mean 'abs'?
  124 |       cout<<ans<<endl;
      |             ^~~
      |             abs