[프로그래머스]행렬 테두리 회전하기

• 문제

• 해설

def get_rotation_candidates(mat, query):
    x1, y1, x2, y2 = query
    # (x, y, val)
    first = [(x1-1, y1 -1 + i, mat[x1-1][y1-1+i]) for i in range(y2-y1)]
    second = [(x1-1+i, y2-1, mat[x1-1+i][y2-1]) for i in range(x2-x1)]
    third = [(x2-1, y2-1-i, mat[x2-1][y2-1-i]) for i in range(y2-y1)]
    fourth = [(x2-1-i,y1-1, mat[x2-1-i][y1-1]) for i in range(x2-x1)]    
    return first, second, third, fourth

def get_min(first, second, third, fourth):
    return min(
        min(first, key=lambda x: x[2])[2],
        min(second, key=lambda x: x[2])[2], 
        min(third, key=lambda x: x[2])[2], 
        min(fourth, key=lambda x: x[2])[2], 
    )

def rotate(mat, first, second, third, fourth):
    mat[first[0][0]][first[0][1]] = fourth[-1][-1]
    mat[second[0][0]][second[0][1]] = first[-1][-1]
    mat[third[0][0]][third[0][1]] = second[-1][-1]
    mat[fourth[0][0]][fourth[0][1]] = third[-1][-1]

    if len(first) >= 2:
        for i in range(1, len(first)):
            new_val = first[i-1][-1]
            mat[first[i][0]][first[i][1]] = new_val
    if len(second) >= 2:
        for i in range(1, len(second)):
            new_val = second[i-1][-1]
            mat[second[i][0]][second[i][1]] = new_val
    if len(third) >= 2:
        for i in range(1, len(third)):
            new_val = third[i-1][-1]
            mat[third[i][0]][third[i][1]] = new_val
    if len(fourth) >= 2:
        for i in range(1, len(fourth)):
            new_val = fourth[i-1][-1]
            mat[fourth[i][0]][fourth[i][1]] = new_val    
    return mat

def solution(rows, columns, queries):
    init_mat = [[i for i in range(1 + (j-1)*columns, 1 + j * columns)] for j in range(1, 1 + rows)]
    mins = []
    for query in queries:
        first, second, third, fourth = get_rotation_candidates(init_mat, query)
        mins.append(get_min(first, second, third, fourth))
        init_mat = rotate(init_mat, first, second, third, fourth)
    return mins

• 포인트
  • min(listOfTuples, key=lambda x: x[2])[2] 을 통해 third element 최솟값 얻기
  • 테두리를 4분할해서 처리, 각 분할마다 첫점과 그 외를 나눠 해결