Solución del grupo "josep_pon" de la Semic Challenge de la HackEPS 2017

hackeps-2017-challenge-1.cpp

#include <algorithm>
#include <iostream>
#include <fstream>
#include <string>

const unsigned MAX_NUM = 1000000;
const unsigned char NOT_KNOWN = 0;
const unsigned char KNOWN_GOOD = 1;
const unsigned char KNOWN_BAD = 2;

int reverse_integer(int n)
{
    int reversed_number = 0;
    int remainder;
    while(n != 0)
    {
        remainder = n % 10;
        reversed_number = reversed_number * 10 + remainder;
        n /= 10;
    }
    return reversed_number;
}


bool is_super_reverse(int n) 
{
    if (n < 10) { return false; }
    int rev = reverse_integer(n);
    int sum = rev + n;
    std::string str = std::to_string(sum);
    return std::count(str.begin(), str.end(), str[0]) == str.size();
}


int main(int argc, char** argv)
{
    int cases, begin, end;
    int known_data[MAX_NUM];

    int counter = 0;
    for (int i = 0; i < MAX_NUM; ++i) {
        if (is_super_reverse(i)) { counter += 1; }
        known_data[i] = counter;
    }

    std::cin >> cases;
    for (unsigned i = 0; i < cases; ++i) {
        std::cin >> begin >> end;
        int count = known_data[end] - known_data[begin];
        if (is_super_reverse(begin)) { count += 1; }
        std::cout << "Case #" << (i + 1) << ": " << count << std::endl; 
    }
}