[Leetcode] 592. Fraction Addition and Subtraction

public class Fraction {

    public boolean symbol;

    //numerator/denominator
    public int denominator;
    public int numerator;

    public Fraction(int denominator,int numerator,boolean symbol){
        this.denominator = denominator;
        this.numerator = numerator;
        this.symbol = symbol;
    }

    @Override
    public String toString(){
        String sym = symbol? "" : "-";
        return sym + numerator + "/" + denominator;
    }

}


public Solution{
//region 592. Fraction Addition and Subtraction
    public String fractionAddition(String expression) {
        Fraction result = new Fraction(1,0,true);
        char[] expressionArray = expression.toCharArray();

        boolean symbol = true;
        int numerator = 0;
        int denominator = 1;
        boolean isAfterSlash = false;
        boolean isFirstNum = true;
        for (int i = 0; i < expressionArray.length; i ++){
            //if it is '-'
            if(expressionArray[i] == '-'){
                if(i==0){
                    symbol = false;
                }else {
                    result = fractionAdd(result,new Fraction(denominator,numerator,symbol));
                    symbol = false;
                    numerator = 0;
                    denominator = 1;
                    isAfterSlash = false;
                    isFirstNum = true;
                }
            }else if (expressionArray[i] == '+'){
                result = fractionAdd(result,new Fraction(denominator,numerator,symbol));
                symbol = true;
                numerator = 0;
                denominator = 1;
                isAfterSlash = false;
                isFirstNum = true;
            }else if (expressionArray[i] == '/'){
                isAfterSlash = true;
                isFirstNum = true;
            }else {
                if(isAfterSlash){
                    denominator = isFirstNum? expressionArray[i] - '0' : denominator*10 + expressionArray[i] - '0';
                    isFirstNum = false;
                }else {
                    numerator = isFirstNum? expressionArray[i] - '0' : numerator*10 + expressionArray[i] - '0';
                    isFirstNum = false;
                }
                if(i == expressionArray.length -1){
                    result = fractionAdd(result,new Fraction(denominator,numerator,symbol));
                }
            }
        }
        return result.toString();
    }

    public Fraction fractionAdd(Fraction frac1, Fraction frac2){
        int maxDenominator = getLeastCommonMultiple(new int[]{frac1.denominator,frac2.denominator});
        int newNumerator1 = frac1.numerator * (maxDenominator/frac1.denominator);
        int newNumerator2 = frac2.numerator * (maxDenominator/frac2.denominator);
        int totalNumerator = (frac1.symbol?newNumerator1:-newNumerator1) +
                (frac2.symbol?newNumerator2:-newNumerator2);

        boolean newSymbol = totalNumerator >= 0;
        return fractionReducible(maxDenominator,Math.abs(totalNumerator),newSymbol);

    }

    public Fraction fractionReducible(int denominator, int numerator, boolean symbol){
        int maxDenominator = getGreatCommonDivisor(new int[]{denominator, numerator});
        return new Fraction(
                denominator/maxDenominator,
                numerator/maxDenominator,
                symbol);
    }

    public int getGreatCommonDivisor(int[] numArray){
        if(numArray[0]==0 || numArray[1]==0){
            return numArray[0] ==0? numArray[1]: numArray[0];
        }
        int remainder = Integer.MAX_VALUE;
        while (remainder != 0){
            int temp = numArray[0] % numArray[1];
            if(temp != 0){
                numArray[0] = numArray[1];
                numArray[1] = temp;
            }
            remainder = temp;
        }
        return numArray[1];
    }

    public int getLeastCommonMultiple(int[] numArray){
        return numArray[0]*numArray[1]/getGreatCommonDivisor(numArray);
    }
    //endregion
}