[Java] 프로그래머스 - 교점에 별 만들기

1월 15일(월) - 3장 배열

프로그래머스

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import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

public class Solution {

    private static class Point{
        public long x,y;

        private Point(long x, long y){
            this.x = x;
            this.y = y;
        }
    }

    private Point intersection(long a1, long b1, long c1, long a2, long b2, long c2){
        double x = (double) (b1*c2 - b2*c1) / (a1*b2 - a2*b1);
        double y = (double) (a2*c1 - a1*c2) / (a1*b2 - a2*b1);

        if(x%1 != 0 || y%1 !=0)
        {
            return null;
        }

        return new Point((long)x, (long)y);
    }

    private Point get_min_point(List<Point> points){
        long x = Long.MAX_VALUE;
        long y = Long.MAX_VALUE;

        for(Point p : points)
        {
            if(p.x < x)
            {
                x = p.x;
            }
            if(p.y < y)
            {
                y = p.y;
            }
        }

        return new Point(x,y);
    }

    private Point get_max_point(List<Point> points){
        long x = Long.MIN_VALUE;
        long y = Long.MIN_VALUE;

        for(Point p : points)
        {
            if(p.x > x)
            {
                x = p.x;
            }
            if(p.y > y)
            {
                y = p.y;
            }
        }

        return new Point(x,y);
    }

    public String[] solution(int[][] line){
        List<Point> points = new ArrayList<>();
        for(int i=0; i< line.length; i++)
        {
            for(int j=i+1; j< line.length; j++)
            {
                Point intersection = intersection(line[i][0], line[i][1], line[i][2], line[j][0], line[j][1], line[j][2]);
                if(intersection != null)
                {
                    points.add(intersection);
                }
            }
        }

        Point min = get_min_point(points);
        Point max = get_max_point(points);

        int width = (int)(max.x - min.x + 1);
        int height = (int)(max.y - min.y + 1);

        char[][] arr = new char[height][width];
        for(char[] row : arr)
        {
            Arrays.fill(row,'.');
        }

        for(Point p : points)
        {
            int x = (int)(p.x - min.x);
            int y = (int)(max.y - p.y);
            arr[y][x] = '*';
        }

        String[] result = new String[arr.length];
        for(int i=0; i< result.length; i++)
        {
            result[i] = new String(arr[i]);
        }
        
        return result;

    }

}

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