Solving distance of two cities

distance.java

double perfectCity(double[] departure, double[] destination) {
    double minorVert = 0; 
    double minorHor = 0;
    
    minorVert = minorDistance(departure[1], destination[1]);
    minorHor = minorDistance(departure[0], destination[0]);
    
    return minorVert + minorHor;
}

double minorDistance(double a, double b) {
    if (a == b) return 0;
    
    if (!isInBetween(a, b)) {
        double left = floor(a);
        left = (a - left) + (b - left);
        double right = ceil(a);
        right = (right - a) + (right - b);
        
        double result = left < right?left:right;
        //result = result % 1.0;
        
        return result;
    } else {
        double min = min(a, b);
        double max = max(a,b);
        double minRight = ceil(min);
        
        double result = (minRight - min) + (max - minRight);
        //result = result = result % 1.0;
        
        return result;
    }
}

double min(double a, double b) {
    return a < b?a:b;
}

double max(double a, double b) {
    return a > b?a:b;
}

/**
 * Check wether there is road between them.
 * @return true if there is road(s) between a and b. 
 */ 
boolean isInBetween(double a, double b) {
    if (a < 0.0 && b > 0.0) return true;
    if (a > 0.0 && b < 0.0) return true;
    if (floor(a) != floor(b)) return true;
    return false;
}

double abs(double input) {
    if (input > 0.0) return input;
    return 0.0 - input;
}

double floor(double input) {
    double result = input - (input % 1.0);
    return result;
}

double ceil(double input) {
    if (input % 1.0 == 0.0) {
        return input;
    }
    return floor(input) + 1;
}