[백준] 2667 - 단지번호붙이기(설명X)

#include <cstdio>
#include <queue>
using namespace std;
 
int bfs(int** arr, int** visited, int size, int x, int y) {
    queue<pair<int, int>> order;
    order.push({ x, y });
    int num = 0;
    visited[x][y] = 1;
    while (!order.empty()) {
        pair<int, int> now = order.front();
        order.pop();
        num++;
 
        if (now.first + 1 < size && arr[now.first + 1][now.second] == 1 && visited[now.first + 1][now.second] == 0) {
            order.push({ now.first + 1, now.second });
            visited[now.first + 1][now.second] = 1;
        }
        if (now.first - 1 >= 0 && arr[now.first - 1][now.second] == 1 && visited[now.first - 1][now.second] == 0) {
            order.push({ now.first - 1, now.second });
            visited[now.first - 1][now.second] = 1;
        }
        if (now.second + 1 < size && arr[now.first][now.second + 1] == 1 && visited[now.first][now.second + 1] == 0) {
            order.push({ now.first, now.second + 1 });
            visited[now.first][now.second + 1] = 1;
        }
        if (now.second - 1 >= 0 && arr[now.first][now.second - 1] == 1 && visited[now.first][now.second - 1] == 0) {
            order.push({ now.first, now.second - 1 });
            visited[now.first][now.second - 1] = 1;
        }
    }
    return num;
}
 
int main() {
    int N;
    scanf("%d", &N);
    priority_queue<int, vector<int>, greater<int>> pqueue;
    int** arr = new int* [N];
    for (int i = 0; i < N; i++) {
        arr[i] = new int[N];
        for (int j = 0; j < N; j++)
            scanf("%1d", &arr[i][j]);
    }
    int** visited = new int* [N];
    for (int i = 0; i < N; i++)
        visited[i] = new int[N] {0, };
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            if (arr[i][j] == 1 && visited[i][j] == 0)
                pqueue.push(bfs(arr, visited, N, i, j));
        }
    }
    printf("%d\n", pqueue.size());
    while (!pqueue.empty()) {
        printf("%d\n", pqueue.top());
        pqueue.pop();
    }
}