#include <iostream>
#include <vector>
#include <random>
#include <algorithm>
#include <unordered_set>
/*
Function: has_all_unique_digits
Purpose: Check whether an integer contains only distinct digits.
Example: 123 → true, 112 → false.
*/
bool has_all_unique_digits(int n) {
std::unordered_set<int> seen;
while (n > 0) {
int d = n % 10;
if (seen.count(d)) return false; // digit already seen → not unique
seen.insert(d);
n /= 10;
}
return true;
}
/*
Function: generate_unique_digit_int
Purpose: Generate a random integer with all digits distinct.
Uses C++'s <random> for high‑quality randomness.
*/
int generate_unique_digit_int(int min_val, int max_val, std::mt19937 &rng) {
std::uniform_int_distribution<int> dist(min_val, max_val);
while (true) {
int candidate = dist(rng);
if (has_all_unique_digits(candidate)) {
return candidate; // return only when digits are distinct
}
}
}
/*
Function: generate_three_unique_digit_integers
Purpose: Produce exactly three integers, each with distinct digits.
Ensures they are also distinct from each other.
*/
std::vector<int> generate_three_unique_digit_integers(int min_val, int max_val) {
std::random_device rd;
std::mt19937 rng(rd());
std::unordered_set<int> results;
while (results.size() < 3) {
int val = generate_unique_digit_int(min_val, max_val, rng);
results.insert(val); // set ensures no duplicates
}
return std::vector<int>(results.begin(), results.end());
}
int main() {
// Generate three integers between 100 and 999 (all 3-digit numbers)
auto nums = generate_three_unique_digit_integers(100, 999);
std::cout << "Generated integers with distinct digits:\n";
for (int n : nums) {
std::cout << n << "\n";
}
}
/*
run:
Generated integers with distinct digits:
783
948
938
*/
