USACO 1.2 Dual Palindrome

Another implementation skill test for base conversion.

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

using namespace std;

bool isPalindrome(string str) {
  for (int i = 0, j = str.size() - 1; i < j; ++i, --j) {
    if (str[i] != str[j]) return false;
  }

  return true;
}

string getNumber(int number, int BASE) {
  string str;
  int base = BASE;
  while (number) {
    int digit = number % base;
    int factor = base / BASE;
    digit /= factor;
    str.push_back(digit + '0');
    number -= digit * factor;
    base *= BASE;
  }

  return str;
}

int main() {
  ifstream fin("dualpal.in");
  ofstream fout("dualpal.out");

  int N, S;
  fin >> N >> S;

  for (int i = S + 1, j = 0; j < N;) {
    int count = 0;
    for (int k = 2; k <= 10; ++k) {
      if (j > N) break;
      string num = getNumber(i, k);
      if (isPalindrome(num)) {
        ++count;
        if (count == 2) {
          fout << i << std::endl;
          ++j; ++i;
          break;
        }
      }
    }

    if (count != 2) ++i;
  }

  return 0;
}