[BAEKJOON] 20057번: 마법사 상어와 토네이도

이름 구려

문제 설명

DFS도 BFS도 아닌 시뮬레이션 문제. 처음 풀어보는 유형이라 그냥 진짜 부딪쳐 보는 수밖에 없다.
다른 사람의 코드를 하나하나 뜯어보면서 어떤 알고리즘인지 학습했다.

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def move(x, y, d):
    global answer

    total = area[x][y]
    five_percent = int(total*5/100)
    ten_percent = int(total*10/100)
    seven_percent = int(total*7/100)
    one_percent = int(total*1/100)
    two_percent = int(total*2/100)
    
    a_x, a_y = x+dx[d], y+dy[d]    # 앞쪽 1칸
    b_x, b_y = x-dx[d], y-dy[d]    # 뒤쪽 1칸
    five_x, five_y = x+2*dx[d], y+2*dy[d]    # 앞쪽 2칸
    
    if d==0 or d==2:    # 왼쪽 or 오른쪽
        ten_list = [(a_x+1, a_y), (a_x-1, a_y)]
        seven_list = [(x+1, y), (x-1, y)]
        one_list = [(b_x+1, b_y), (b_x-1, b_y)]
        two_list = [(x+2, y), (x-2, y)]
    elif d==1 or d==3:
        ten_list = [(a_x, a_y+1), (a_x, a_y-1)]
        seven_list = [(x, y+1), (x, y-1)]
        one_list = [(b_x, b_y+1), (b_x, b_y-1)]
        two_list = [(x, y+2), (x, y-2)]
    
    # 5% 구역
    if (0 <= five_x < n) and (0 <= five_y < n):
        area[five_x][five_y] += five_percent
    else:
        answer += five_percent
    total -= five_percent
    
    # 10% 구역
    for (ten_x, ten_y) in ten_list:
        if (0 <= ten_x < n) and (0 <= ten_y < n):
            area[ten_x][ten_y] += ten_percent
        else:
            answer += ten_percent
        total -= ten_percent
        
    # 7% 구역
    for (seven_x, seven_y) in seven_list:
        if (0 <= seven_x < n) and (0 <= seven_y < n):
            area[seven_x][seven_y] += seven_percent
        else:
            answer += seven_percent
        total -= seven_percent

    # 1% 구역
    for (one_x, one_y) in one_list:
        if (0 <= one_x < n) and (0 <= one_y < n):
            area[one_x][one_y] += one_percent
        else:
            answer += one_percent
        total -= one_percent
        
    # 2% 구역
    for (two_x, two_y) in two_list:
        if (0 <= two_x < n) and (0 <= two_y < n):
            area[two_x][two_y] += two_percent
        else:
            answer += two_percent
        total -= two_percent
        
    # 알파 구역: 남은 모래    
    if (0 <= a_x < n) and (0 <= a_y < n):
        area[a_x][a_y] += total
    else:
        answer += total
    
    area[x][y] = 0
    

n = int(input())
area = [list(map(int, input().split())) for _ in range(n)]
dx = [0, 1, 0, -1]
dy = [-1, 0, 1, 0]
x = n // 2        # 시작 x좌표
y = n // 2        # 시작 y좌표

count = 0
length = 1        # 이동 칸 수
direction = 0    # dx, dy 인덱스

answer = 0

while (0<=x<n) and (0<=y<n):
    count += 1
    
    for i in range(length):
        x += dx[direction]
        y += dy[direction]
        
        if (0<=x<n) and (0<=y<n):
            move(x, y, direction)

    direction = (direction + 1) % 4
    
    if count == 2:
        count = 0
        length += 1

print(answer)