Language: C++

#include "bits/stdc++.h"
#include<unordered_map>
#pragma warning(disable:4996)
using namespace std;




const int mod = 1000000007;
struct Mod {
public:
	int num;
	Mod() : num(0) { ; }
	Mod(long long int n) : num((n % mod + mod) % mod) { ; }
	Mod(int n) : num((n % mod + mod) % mod) { ; }
	operator int() { return num; }
};

Mod operator+(const Mod a, const Mod b) { return Mod((a.num + b.num) % mod); }
Mod operator+(const long long int a, const Mod b) { return Mod(a) + b; }
Mod operator+(const Mod a, const long long int  b) { return b + a; }
Mod operator++(Mod &a) { return a + Mod(1); }
Mod operator-(const Mod a, const Mod b) { return Mod((mod + a.num - b.num) % mod); }
Mod operator-(const long long int a, const Mod b) { return Mod(a) - b; }
Mod operator--(Mod &a) { return a - Mod(1); }
Mod operator*(const Mod a, const Mod b) { return Mod(((long long)a.num * b.num) % mod); }
Mod operator*(const long long int a, const Mod b) { return Mod(a)*b; }

Mod operator*(const Mod a, const int b) { return Mod(b)*a; }
Mod operator+=(Mod &a, const Mod b) { return a = a + b; }
Mod operator+=(long long int &a, const Mod b) { return a = a + b; }
Mod operator-=(Mod &a, const Mod b) { return a = a - b; }
Mod operator-=(long long int &a, const Mod b) { return a = a - b; }
Mod operator*=(Mod &a, const Mod b) { return a = a * b; }
Mod operator*=(long long int &a, const Mod b) { return a = a * b; }
Mod operator^(const Mod a, const int n) {
	if (n == 0) return Mod(1);
	Mod res = (a * a) ^ (n / 2);
	if (n % 2) res = res * a;
	return res;
}
Mod mod_pow(const Mod a, const int n) {
	if (n == 0) return Mod(1);
	Mod res = mod_pow((a * a), (n / 2));
	if (n % 2) res = res * a;
	return res;
}
Mod inv(const Mod a) { return a ^ (mod - 2); }
Mod operator/(const Mod a, const Mod b) {
	assert(b.num != 0);
	return a * inv(b);
}
Mod operator/(const long long int a, const Mod b) {
	assert(b.num != 0);
	return Mod(a) * inv(b);
}
Mod operator/=(Mod &a, const Mod b) {
	assert(b.num != 0);
	return a = a * inv(b);
}

#define MAX_MOD_N 1024000

Mod fact[MAX_MOD_N], factinv[MAX_MOD_N];
void init() {
	fact[0] = Mod(1); factinv[0] = 1;
	for (int i = 0; i < MAX_MOD_N - 1; ++i) {
		fact[i + 1] = fact[i] * Mod(i + 1);
		factinv[i + 1] = factinv[i] / Mod(i + 1);
	}
}
Mod comb(const int a, const int b) {
	return fact[a] * factinv[b] * factinv[a - b];
}

int main() {
	int N, P; cin >> N >> P;
	vector<int>nums;
	for (int i = 0; i < N; ++i) {
		int a; cin >> a;
		nums.push_back(a);
	}
	sort(nums.begin(), nums.end());
	Mod ans = 1;
	for (auto it = nums.begin(); it != nums.end();++it) {
		auto jt = lower_bound(nums.begin(), nums.end(), *it - P);
		ans *= it-jt+1;
	}
	cout << ans << endl;
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:87:29: error: conversion from '__gnu_cxx::__normal_iterator<int*, std::vector<int> >::difference_type' {aka 'long int'} to 'Mod' is ambiguous
   87 |                 ans *= it-jt+1;
      |                        ~~~~~^~
a.cc:15:9: note: candidate: 'Mod::Mod(int)'
   15 |         Mod(int n) : num((n % mod + mod) % mod) { ; }
      |         ^~~
a.cc:14:9: note: candidate: 'Mod::Mod(long long int)'
   14 |         Mod(long long int n) : num((n % mod + mod) % mod) { ; }
      |         ^~~
a.cc:34:34: note:   initializing argument 2 of 'Mod operator*=(Mod&, Mod)'
   34 | Mod operator*=(Mod &a, const Mod b) { return a = a * b; }
      |                        ~~~~~~~~~~^