[Java]프로그래머스 Lv. 0 평행

https://school.programmers.co.kr/learn/courses/30/lessons/120875

프로그래머스

나의 풀이

class Solution {
    public int solution(int[][] dots) {
        int x1 = dots[0][0];
        int y1 = dots[0][1];
        int x2 = dots[1][0];
        int y2 = dots[1][1];
        int x3 = dots[2][0];
        int y3 = dots[2][1];
        int x4 = dots[3][0];
        int y4 = dots[3][1];

        if ((double) (y1 - y2) / (x1 - x2) == (double) (y3 - y4) / (x3 - x4)) return 1;
        if ((double) (y1 - y3) / (x1 - x3) == (double) (y2 - y4) / (x2 - x4)) return 1;
        if ((double) (y1 - y4) / (x1 - x4) == (double) (y2 - y3) / (x2 - x3)) return 1;

        return 0;
    }
}

다른 풀이

import java.util.HashMap;
import java.util.Map;

class Solution {
    public int solution(int[][] dots) {

        Map<Double, Double> straightInfoMap = new HashMap<>();

        for (int i = 0; i < dots.length - 1; i++) {
            for (int j = i + 1; j < dots.length; j++) {
                double slope = Math.abs((double) (dots[j][1] - dots[i][1]) / (double) (dots[j][0] - dots[i][0]));
                double y_intercept =  ((double) (dots[j][1]) - slope * dots[j][0]);
                if (straightInfoMap.containsKey(slope) && straightInfoMap.get(slope) != y_intercept)
                    return 1;
                straightInfoMap.put(slope, y_intercept);
            }
        }

        System.out.println(straightInfoMap);

        return 0;
    }
}