#include <iostream>
#include <vector>
#include <random>
#include <algorithm>
/*
Generate N integers, each with exactly M distinct digits.
Constraints:
- Each integer has length M.
- All digits in a given integer are distinct (no repetition).
- Leading zero is not allowed.
- Digits are chosen randomly.
*/
// Generate one integer with exactly M distinct digits
std::string generateOne(int M, std::mt19937& rng) {
// All possible digits
std::vector<char> digits;
digits.reserve(10);
for (char d = '0'; d <= '9'; ++d)
digits.push_back(d);
// Shuffle digits to get randomness
std::shuffle(digits.begin(), digits.end(), rng);
// Ensure first digit is not zero:
// If '0' ended up at the front, swap it with some non-zero digit.
if (digits[0] == '0') {
// Find first non-zero digit
auto it = std::find_if(digits.begin() + 1, digits.end(),
[](char c) { return c != '0'; });
if (it != digits.end())
std::swap(digits[0], *it);
}
// Now take the first M digits as our distinct digits
std::string result;
result.reserve(M);
for (int i = 0; i < M; ++i)
result.push_back(digits[i]);
return result;
}
// Generate N integers with exactly M distinct digits
std::vector<std::string> generateMany(int N, int M) {
std::random_device rd;
std::mt19937 rng(rd());
std::vector<std::string> results;
results.reserve(N);
for (int i = 0; i < N; ++i)
results.push_back(generateOne(M, rng));
return results;
}
int main() {
int N = 10; // how many integers to generate
int M = 3; // how many distinct digits per integer
std::vector<std::string> results = generateMany(N, M);
std::cout << "Generated integers:\n";
for (const auto& num : results)
std::cout << num << "\n";
return 0;
}
/*
run:
Generated integers:
973
208
831
708
482
837
403
507
176
317
*/
