Compile-Time Timer Reload

#include <iostream>
using namespace std;

// Define constexpr computeReload here
constexpr int computeReload(int clockHz, int intervalMs) {
    return (clockHz * intervalMs + 500) / 1000;  // integer rounding
}

// Define constexpr RELOAD_TABLE here
constexpr int timerClockHz = 1'000'000; // 1 MHz
constexpr int RELOAD_TABLE[3] = {
    computeReload(timerClockHz, 1),    // 1 ms
    computeReload(timerClockHz, 10),   // 10 ms
    computeReload(timerClockHz, 100)   // 100 ms
};

int main() {
    int idx;
    cin >> idx;

    // Print RELOAD_TABLE[idx]
    cout << RELOAD_TABLE[idx];

    return 0;
}

Solving Approach