Baekjoon #16234

#include<bits/stdc++.h>

using namespace std;

int dy[4] = {-1, 1, 0, 0};
int dx[4] = {0, 0, -1, 1};
int N;
int a[55][55];
bool vis[55][55];
int L, R;

bool valid(int y, int x) {
	return 0 <= y && y < N && 0 <= x && x < N;
}

bool bfs() {
	bool flag = false;
	queue<pair<int,int>> q;
	vector<vector<pair<int,int>>> comp;
	vector<int> comp_pop;
	memset(vis, false, sizeof(vis));
	// bfs
	for(int i=0;i<N;++i) {
		for(int j=0;j<N;++j) {
			if(vis[i][j]) continue;
			vector<pair<int,int>> cur;
			int sum = 0;
			q.emplace(i, j);
			vis[i][j] = true;
			while(!q.empty()) {
				int y = q.front().first;
				int x = q.front().second;
				q.pop();
				sum += a[y][x];
				cur.emplace_back(y, x);
				for(int k=0;k<4;++k) {
					int ny = y + dy[k];
					int nx = x + dx[k];
					int diff = abs(a[y][x] - a[ny][nx]);
					if(!valid(ny, nx) || vis[ny][nx]) continue;
					if(diff > R || diff < L) continue;
					flag = true;
					vis[ny][nx] = true;
					q.emplace(ny, nx);
				}
			}
			comp.push_back(cur);
			comp_pop.push_back(sum);
		}
	}
	if(!flag) return false;
	// population moving
	for(int i=0;i<comp.size();++i) {
		int pop = comp_pop[i] / comp[i].size();
		for(pair<int, int> p : comp[i]) a[p.first][p.second] = pop;
	}
	return true;
}

int main() {
	cin.tie(nullptr); ios::sync_with_stdio(false);
	cin >> N >> L >> R;
	for(int i=0;i<N;++i) {
		for(int j=0;j<N;++j) {
			cin >> a[i][j];
		}
	}
	int ans = 0;
	while(bfs()) ++ans;
	cout << ans << '\n';
	return 0;
}

import sys
from collections import deque

def input():
    return sys.stdin.readline().rstrip()

def BFS(x,y):
    global flag, total
    queue = deque()
    queue.append((x,y))
    ans.append((x,y))
    while queue:
        q = queue.popleft()
        for i in range(4):
            dx = nx[i] + q[0]
            dy = ny[i] + q[1]
            if dx < 0 or dx >= N or dy < 0 or dy >= N:
                continue
            if visited[dx][dy] == 1:
                continue
            if abs(arr[dx][dy] - arr[q[0]][q[1]]) >= L and abs(arr[dx][dy] - arr[q[0]][q[1]]) <= R:
                visited[dx][dy] = 1
                flag = 1
                total += arr[dx][dy]
                queue.append((dx,dy))
                ans.append((dx,dy))

N, L, R = map(int, input().split())
arr = []
day = 0
nx = [-1, 0, 1, 0]
ny = [0, -1, 0, 1]
for i in range(N):
    arr.append(list(map(int, input().split())))
while True:
    flag = 0
    visited = [[0 for i in range(N)] for j in range(N)]
    for i in range(N):
        for j in range(N):
            if visited[i][j] == 0:
                ans = deque()
                total = arr[i][j]
                visited[i][j] = 1
                BFS(i,j)
                if len(ans) > 1:
                    aver = total // len(ans)
                    while ans:
                        a = ans.popleft()
                        arr[a[0]][a[1]] = aver
    if not flag:
        break
    day += 1
print(day)