USACO 1.2 Palindrome Square

This problem is very straightforward to solve, just pay attention to implementation details.

#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, const vector<int> &table) {
  string str;
  int base = BASE;
  while (number) {
    int digit = number % base;
    int factor = base / BASE;
    digit /= factor;
    str.push_back(table[digit]);
    number -= digit * factor;
    base *= BASE;
  }

  reverse(str.begin(), str.end());
  return str;
}

int main() {

  vector<int> table = { '0' , '1' , '2' , '3' , '4' , '5' , '6' , '7' , '8' , '9' ,
    'A' , 'B' , 'C' , 'D' , 'E' , 'F' , 'G' , 'H' , 'I' , 'J' } ;

  ifstream fin("palsquare.in");
  ofstream fout("palsquare.out");

  int BASE;
  fin >> BASE;
  for (int i = 1; i <= 300; ++i) {
    string num = getNumber(i * i, BASE, table);
    if (isPalindrome(num)) {
      fout << getNumber(i, BASE, table) << " ";
      fout << num << std::endl;
    }
  }

  return 0;
}