No. 55 - Translating Numbers to Strings : solution

getTransCount.cpp

//http://codercareer.blogspot.kr/2014/09/no-55-translating-numbers-to-string.html
#include <iostream>
#include <string>
#include <assert.h>

using namespace std;

int getTransCount(string number) {
  if (atoi(number.c_str()) <= 0)
    return 0;

  int length = number.length();
  int counts[length] = {0,};

  for (int i = length - 1; i >= 0; --i) {
    int count = 0;
    if (number[i] >= '1' && number[i] <= '9') {
      if (i < length - 1) {
        count += counts[i + 1];
      } else {
        count += 1;
      }
    }

    if (i < length - 1) {
      int digit1 = number[i] - '0';
      int digit2 = number[i + 1] - '0';
      int converted = digit1 * 10 + digit2;
      if (converted >= 10 && converted <= 26) {
        if (i < length - 2) {
          count += counts[i + 2];
        } else {
          count += 1;
        }
      }
    }

    counts[i] = count;
  }

  return counts[0];
}

int main() {
  assert(getTransCount("1") == 1);
  assert(getTransCount("11") == 2);
  assert(getTransCount("100") == 0);
  assert(getTransCount("427") == 1);
  assert(getTransCount("12258") == 5);
  //assert(getTransCount("12258") == 6);
   
  return 0;
}