지형 이동

https://school.programmers.co.kr/learn/courses/30/lessons/62050

queue를 이용. 

from heapq import heappop, heappush


def solution(land, height):
    answer = 0
    que = [(0, 0, 0)]
    visited = set()
    while que:
        p, y, x = heappop(que)
        if (y, x) in visited:
            continue
        visited.add((y, x))
        answer += p
        for dy, dx in ((0, 1), (0, -1), (1, 0), (-1, 0)):
            next_y, next_x = y + dy, x + dx
            if not (len(land) > next_y >= 0 and len(land) > next_x >= 0):
                continue
            if (diff := abs(land[y][x] - land[next_y][next_x])) <= height:
                next_p = 0
            else:
                next_p = diff
            heappush(que, (next_p, next_y, next_x))
    return answer

굳이 줄이려면 줄일 수도 있겠으나.. 가독성이.. 

from heapq import heappop, heappush


def solution(land, height):
    answer = 0
    que = [(0, 0, 0)]
    visited = set()
    while que:
        p, y, x = heappop(que)
        if (y, x) not in visited:
            visited.add((y, x))
            answer += p
            for dy, dx in ((0, 1), (0, -1), (1, 0), (-1, 0)):
                next_y, next_x = y + dy, x + dx
                if len(land) > next_y >= 0 and len(land) > next_x >= 0:
                    heappush(que, (0 if (diff := abs(land[y][x] - land[next_y][next_x])) <= height else diff, next_y, next_x))
    return answer