WordToNumber.java

import java.io.*;
import java.util.*;

public class WordToNumber {
    
    public static void main(String[] args) throws IOException {
        (new WordToNumber()).run();
    }
    
    public void run() throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        
        Stack<Integer> numberStack = new Stack<Integer>();
        
        String input = br.readLine();
        String[] tokens = input.split("[ ,]");
        
        for (String token : tokens) {
            int digitValue = getDigitValue(token);
            if (digitValue != -1) {
                numberStack.push(digitValue);
            }
            else if (token.equals("ten")) {
                numberStack.push(10);
            }
            else if (token.equals("eleven")) {
                numberStack.push(11);
            }
            else if (token.equals("twelve")) {
                numberStack.push(12);
            }
            else if (token.equals("thirteen")) {
                numberStack.push(13);
            }
            else if (token.equals("fourteen")) {
                numberStack.push(14);
            }
            else if (token.equals("fifteen")) {
                numberStack.push(15);
            }
            else if (token.equals("sixteen")) {
                numberStack.push(16);
            }
            else if (token.equals("seventeen")) {
                numberStack.push(17);
            }
            else if (token.equals("eighteen")) {
                numberStack.push(18);
            }
            else if (token.equals("nineteen")) {
                numberStack.push(19);
            }
            else if (token.equals("thousand")) {
                int currentNumber = numberStack.pop();
                if (!numberStack.empty() && numberStack.peek() >= 100) {
                    currentNumber += numberStack.pop();
                }
                numberStack.push(currentNumber * 1000);
            }
            else if (token.equals("hundred")) {
                int currentNumber = numberStack.pop();
                numberStack.push(currentNumber * 100);
            }
            else if (token.startsWith("twenty")) {
                numberStack.push(getTwoDigitTokenValue(token, 20));
            }
            else if (token.startsWith("thirty")) {
                numberStack.push(getTwoDigitTokenValue(token, 30));
            }
            else if (token.startsWith("forty")) {
                numberStack.push(getTwoDigitTokenValue(token, 40));
            }
            else if (token.startsWith("fifty")) {
                numberStack.push(getTwoDigitTokenValue(token, 50));
            }
            else if (token.startsWith("sixty")) {
                numberStack.push(getTwoDigitTokenValue(token, 60));
            }
            else if (token.startsWith("seventy")) {
                numberStack.push(getTwoDigitTokenValue(token, 70));
            }
            else if (token.startsWith("eighty")) {
                numberStack.push(getTwoDigitTokenValue(token, 80));
            }
            else if (token.startsWith("ninety")) {
                numberStack.push(getTwoDigitTokenValue(token, 90));
            }
        }
        
        int sum = 0;
        for (int x : numberStack) {
            sum += x;
        }
        
        System.out.println(sum);
    }
    
    public int getDigitValue(String token) {
        if (token.equals("zero")) {
            return 0;
        }
        if (token.equals("one")) {
            return 1;
        }
        else if (token.equals("two")) {
            return 2;
        }
        else if (token .equals("three")) {
            return 3;
        }
        else if (token .equals("four")) {
            return 4;
        }
        else if (token .equals("five")) {
            return 5;
        }
        else if (token .equals("six")) {
            return 6;
        }
        else if (token .equals("seven")) {
            return 7;
        }
        else if (token .equals("eight")) {
            return 8;
        }
        else if (token .equals("nine")) {
            return 9;
        }
        else {
            return -1;
        }
    }
    
    public int getTwoDigitTokenValue(String token, int prefixValue) {
        String[] twoDigit;
        twoDigit = token.split("-");
        if (twoDigit.length > 1) {
            return prefixValue + getDigitValue(twoDigit[1]);
        }
        else {
            return prefixValue;
        }
    }
}