행렬과 연산

https://school.programmers.co.kr/learn/courses/30/lessons/118670

프로그래머스

 

 

소스코드

import java.util.*;

class Solution {
    public int[][] solution(int[][] rc, String[] operations) {
        int[][] answer = rc;
        
        Deque<Integer> left = new ArrayDeque<>();
        Deque<Integer> right = new ArrayDeque<>();
        Deque<Deque<Integer>> mid = new ArrayDeque<>();

        for (int i = 0; i < rc.length; i++) {
            left.add(rc[i][0]);
            Deque<Integer> midDq = new ArrayDeque<>();
            for (int j = 1; j < rc[0].length - 1; j++) {
                midDq.add(rc[i][j]);
            }
            mid.add(midDq);
            right.add(rc[i][rc[0].length - 1]);
        }

        for (int i = 0; i < operations.length; i++) {
            if(operations[i].equals("ShiftRow")) {
                left.addFirst(left.pollLast());
                right.addFirst(right.pollLast());
                mid.addFirst(mid.pollLast());
            } else {
                mid.peekFirst().addFirst(left.pollFirst());
                right.addFirst(mid.peekFirst().pollLast());
                mid.peekLast().addLast(right.pollLast());
                left.addLast(mid.peekLast().pollFirst());
            }
        }

        for (int i = 0; i < rc.length; i++) {
            answer[i][0] = left.pollFirst();
            Deque<Integer> midDq = mid.pollFirst();
            for (int j = 1; j < rc[0].length - 1; j++) {
                answer[i][j] = midDq.pollFirst();
            }
            answer[i][rc[0].length - 1] = right.pollFirst();
        }

        return answer;
    }
}

 

 

해결방법

위 그림과 같이 left(Deque), mid(Deque<Deque>), right(Deque)로 나누어서 해결하였다.

빨간 표시 => "Rotate"

파란 표시 => "ShiftRow"