[알고리즘 Python] 백준 16234 - 인구 이동

import sys
import heapq
import math
from collections import deque
sys.setrecursionlimit(100000)

dx = [-1,1,0,0]
dy = [0,0,-1,1]

N,L,R = map(int,input().split())
pp = [list(map(int,input().split())) for _ in range(N)]
cnt = 0

def go(x,y) :
    totSum = pp[x][y]
    totGrp = [(x,y)]
    for k in range(4):
        nx,ny = x+dx[k],y+dy[k]
        if 0 <= nx < N and 0 <= ny < N :
            if L <= abs(pp[nx][ny] - pp[x][y]) <= R and ch[nx][ny] == False :
                ch[nx][ny] = True
                tmpSum,tmpGrp = go(nx,ny)
                totSum += tmpSum
                totGrp += tmpGrp 
    return totSum,totGrp

while True:
    change = False
    
    ch    = [[False]*N for _ in range(N)]
    befpp = [list(p) for p in pp]
    
    for i in range(N):
        for j in range(N):
            if ch[i][j] == False:
                ch[i][j] = True
                psum,pgrp = go(i,j)
                pavg = math.floor(psum//len(pgrp))
                for gp in pgrp:
                    x,y = gp
                    pp[x][y] = pavg
    for i in range(N):
        for j in range(N):
            if befpp[i][j] != pp[i][j]:
                change = True
                break
    if not change :
        break
    cnt += 1
print(cnt)