[백준/JAVA] 11758번: CCW

🔺 문제

11758번: CCW

 

 

🔺 코드

import java.util.*;
import java.io.*;
 
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st = new StringTokenizer(br.readLine()," ");
           
        int x1 = Integer.parseInt(st.nextToken());
        int y1 = Integer.parseInt(st.nextToken());
        
        st = new StringTokenizer(br.readLine()," ");   
        int x2 = Integer.parseInt(st.nextToken());
        int y2 = Integer.parseInt(st.nextToken());
        
        st = new StringTokenizer(br.readLine()," ");   
        int x3 = Integer.parseInt(st.nextToken());
        int y3 = Integer.parseInt(st.nextToken());
        
        int ccw = (x1*y2 + x2*y3 + x3*y1) - (x2*y1 + x3*y2 + x1*y3);
        
        if(ccw < 0)       System.out.println(-1);   // 시계 방향
        else if(ccw == 0) System.out.println(0);    // 일직선
        else              System.out.println(1);    //  방향
    }
}

✅ 해결 아이디어
✔ CCW (counter-clockwise)

 

 

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💬 느낀 점

앞에서 복잡(?)한 거 풀다가 이런거 푸니까 맘이 편안하고 막 그래...

 

 

1회독	2회독	3회독	4회독	5회독
V	7/11

 

 

(+7/11 2회독)

 

import java.util.*;
import java.io.*;
 
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        StringTokenizer st;
        
        int[][] pos = new int[3][2];
        
        for(int i = 0 ; i < 3 ; i++) {
            st = new StringTokenizer(br.readLine(), " ");
            pos[i][0] = Integer.parseInt(st.nextToken());
            pos[i][1] = Integer.parseInt(st.nextToken());
        }
        
        long tmp1 = (pos[0][0] * pos[1][1] + pos[1][0] * pos[2][1] + pos[2][0] * pos[0][1]);
        long tmp2 = (pos[1][0] * pos[0][1] + pos[2][0] * pos[1][1] + pos[0][0] * pos[2][1]);
        
        long ccw = tmp1 - tmp2;
        long answer = 0;
        
        if(ccw > 0) answer = 1;
        else if(ccw < 0) answer = -1;
        
        System.out.println(answer);
    }  
}
 

 

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(참고)

✔ Do it 알고리즘 코딩테스트 자바편