문제 링크

https://www.acmicpc.net/problem/17144

문제 설명

• board에 미세먼지, 공기청정기가 주어짐
• 미세먼지 확산, 공기 정화 반복
• t번 반복 후 미세먼지 양 출력

풀이

• 미세먼지 확산
  • 새로운 board를 만들어서 확산된 후 미세먼지 저장
  • 기존 board랑 교체
• 공기 정화
  • 방향 바꿔가며 4줄 swap

코드

def spread():
    global board
    dy, dx = [-1,0,1,0], [0,1,0,-1]
    new_board = [[0 if board[y][x] != -1 else -1 for x in range(c)] for y in range(r)]
    for y in range(r):
        for x in range(c):
            center, side = board[y][x], board[y][x] // 5
            if center <= 0:
                continue
            for d in range(4):
                ny, nx = y + dy[d], x + dx[d]
                if 0 <= ny < r and 0 <= nx < c and board[ny][nx] >= 0:
                    new_board[ny][nx] += side
                    center -= side
            new_board[y][x] += center
    board = new_board


def clean():
    for y in range(r):
        if board[y][0] == -1:
            go(0, y+1, y, -1)
            go(y+1, r, y+1, 1)
            break

# 범위1, 범위2, 시작, 방향
def go(r1, r2, y, d):
    dy, dx = [d,0,-d,0], [0,1,0,-1]
    board[y][0] = 0
    board[y+d][0] = -1
    cy, cx = y, 0
    for d in range(4):
        while True:
            ny, nx = cy + dy[d], cx + dx[d]
            # 마지막 제외
            if ny == y and nx == 0:
                break
            # 벗어날 경우
            if not (r1 <= ny < r2 and 0 <= nx < c):
                break
            board[cy][cx], board[ny][nx] = board[ny][nx], board[cy][cx]
            cy, cx = ny, nx

# init
import sys
read = sys.stdin.readline
r, c, t = map(int, read().split())
board = [list(map(int, read().split())) for _ in range(r)]

# start
for _ in range(t):
    spread()
    clean()
print(sum([sum(board[i]) for i in range(r)]) + 2)