Language: C++

// warm heart, wagging tail,and a smile just for you!
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//                                                                ███╬╬╬╬╬████╬╬╬╬╬╬███
//                                            ███████████       ██╬╬╬╬╬████╬╬████╬╬╬╬╬██
//                                      █████████╬╬╬╬╬████████████╬╬╬╬╬██╬╬╬╬╬╬███╬╬╬╬╬██
//                               ████████╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬█████████╬╬╬╬╬╬██╬╬╬╬╬╬╬██
//                             ████╬██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬█████████╬╬╬╬╬╬╬╬╬╬╬██
//                           ███╬╬╬█╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██╬╬███╬╬╬╬╬╬╬█████
//                         ███╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██╬╬╬████████╬╬╬╬╬██
//                       ███╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬███╬╬╬╬╬╬╬╬╬███
//                     ███╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬█████╬╬╬╬╬╬╬██
//                 ████╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬████╬╬╬╬╬████
//     █████████████╬╬╬╬╬╬╬╬██╬╬╬╬╬████╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬█████╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬███╬╬╬╬██████
//   ████╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██╬╬██████╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██████╬╬╬╬╬╬╬███████████╬╬╬╬╬╬╬╬██╬╬╬██╬╬╬██
// ███╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬████╬╬╬╬╬╬╬╬╬╬╬█╬╬╬╬╬╬╬██╬╬╬╬╬╬╬╬██
// ██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██╬╬╬╬▓▓▓▓▓▓╬╬╬████╬╬████╬╬╬╬╬╬╬▓▓▓▓▓▓▓▓██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██╬╬╬╬╬╬╬███
// ██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██████▓▓▓▓▓▓▓╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬▓▓▓▓▓▓▓██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██╬╬╬╬█████
// ███╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬███╬╬╬╬╬██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬█████╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬████████
//   ███╬╬╬╬╬╬╬╬╬╬╬╬╬█████╬╬╬╬╬╬╬╬██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬███╬╬██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬██
//       ██████████████  ████╬╬╬╬╬╬███████████████████████████╬╬╬╬╬██╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬╬████
//                         ███████                           █████  ███████████████████  
#include "bits/stdc++.h"
using namespace std;
#define MOD 1000000007
#define INF 1LL<<60
#define fs first
#define sc second
#define pb push_back
#define int long long
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define RFOR(i,a,b) for(int i = (b-1);i>=a;i--)
#define REP(i,n)  FOR(i,0,n)
#define RREP(i,n) RFOR(i,0,n)
#define ITR(itr,mp) for(auto itr = (mp).begin(); itr != (mp).end(); ++itr)
#define RITR(itr,mp) for(auto itr = (mp).rbegin(); itr != (mp).rend(); ++itr)
#define range(i,a,b) ((a)<=(i) && (i)<(b))
#define debug(x)  cout << #x << " = " << (x) << endl;
#define SP << " " << 
typedef pair<int,int> P;
typedef vector<vector<P> > Graph;

const int NMAX = 1e6;
vector<int> child,tree(NMAX);
int root(int i){
  if(i == tree[i]){
    REP(j,child.size()) tree[child[j]] = i;
    child.clear(); 
    return i;
  }
  else{
    child.push_back(i);
    return i = root(tree[i]);
  }
}

int unit(int x, int y){
  x = root(x);
  y = root(y);
  tree[max(x,y)] = min(x,y);
}

bool isUnit(int x, int y){
  return root(x) == root(y);
}

void add(int &a, int b){
  a = ((a+b) % MOD + MOD) % MOD;
}

inline int mul(int a, int b) {
    #if !defined(_WIN32) || defined(_WIN64)
      return (int) ((long long) a * b % MOD);
    #endif
      unsigned long long x = (long long) a * b;
      unsigned xh = (unsigned) (x >> 32), xl = (unsigned) x, d, m;
      asm(
        "divl %4; \n\t"
        : "=a" (d), "=d" (m)
        : "d" (xh), "a" (xl), "r" (MOD)
      );
      return m;
}

inline int modpow(int a, long long b) {
  int res = 1;
  while (b > 0) {
    if (b & 1) {
      res = mul(res, a);
      }
      a = mul(a, a);
      b >>= 1;
  }
  return res;
}

inline int inv(int a) {
    a %= MOD;
    if (a < 0) a += MOD;
    int b = MOD, u = 0, v = 1;
    while (a) {
      int t = b / a;
      b -= t * a; swap(a, b);
      u -= t * v; swap(u, v);
    }
    assert(b == 1);
    if (u < 0) u += MOD;
    return u;
}

signed main(){
  ios::sync_with_stdio(false);
  cin.tie(0);  
  //問題文を読む時間をケチらない！！

  int n,x,y;
  cin >> n >> x >> y;

  vector<P> color[n];
  vector<int> c(n),w(n);
  REP(i,n){
    cin >> c[i] >> w[i]; c[i]--;
    color[c[i]].push_back(P(w[i],i));
  }

  REP(i,n) sort(color[i].begin(),color[i].end());
  REP(i,n) tree[i] = i;

  P tmp = P(INF,INF);
  REP(i,n){
    if(color[i].size() == 0) continue;
    tmp = min(tmp,color[i][0]);
    FOR(j,1,color[i].size()){
      if(color[i][0].fs + color[i][j].fs <= x) unit(color[i][0].sc,color[i][j].sc);
    }
  }

  REP(i,n){
    if(c[tmp[i].sc] != c[i] && tmp.fs + w[i] <= y) unit(tmp.sc,i);
  }

  map<int,int> sum[n];
  REP(i,n){
    sum[root(i)][c[i]]++;
  }

  vector<int> fact(n+1,1);
  REP(i,n) fact[i+1] = mul(fact[i],i+1);

  int ans = 1;
  REP(i,n){
    int cnt = 0, pos = 1;
    ITR(itr,sum[i]){
      cnt += itr->sc; //個数
      pos = mul(pos,fact[itr->sc]); // 組み合わせ
    }
    ans = mul(ans,mul(fact[cnt],inv(pos)));
  }

  cout << ans << endl;

  return 0;
}

Compiler output:
a.cc: In function 'long long int unit(long long int, long long int)':
a.cc:61:1: warning: no return statement in function returning non-void [-Wreturn-type]
   61 | }
      | ^
a.cc: In function 'int main()':
a.cc:139:13: error: no match for 'operator[]' (operand types are 'P' {aka 'std::pair<long long int, long long int>'} and 'long long int')
  139 |     if(c[tmp[i].sc] != c[i] && tmp.fs + w[i] <= y) unit(tmp.sc,i);
      |             ^