dfs_百炼 2815 陈堡 (从深度优先遍历做了什么来理解深度优先遍历)

#define _CRT_SECURE_NO_WARNINGS  
#include <stdio.h>
#include <math.h>
#include <algorithm>
#include <stdlib.h>
#include <vector>
#include <map>
#include <queue>
#include <string>
#include <iostream>
#include <ctype.h>
#include <string.h>
#include <set>
#include <stack>
#include<functional>
using namespace std;
#define Size 22
#define maxn  1<<30
#define minn  1e-6
const int dir[4][2] = { { 0, -1 }, { -1, 0 }, { 0, 1 }, { 1, 0 } };

int r, c, rooms = 0, max_area = 0, area;
int wall[Size][Size], visit[Size][Size];

void dfs(int i, int j)
{
    area++;
    visit[i][j] = true;//进行深搜的目的是为了1,标记这一个块,2面积++;
    for (int t = 0; t<4; t++)
        if (!visit[i + dir[t][0]][j + dir[t][1]] && !(wall[i][j] & (1 << t)))
            dfs(i + dir[t][0], j + dir[t][1]);
    return;
}

int main()
{
    scanf("%d%d\n", &r, &c);
    for (int i = 0; i<r; i++)
        for (int j = 0; j<c; j++)
            scanf("%d", &wall[i][j]);
    for (int i = 0; i<r; i++)
        for (int j = 0; j<c; j++)
            if (!visit[i][j])
            {
                rooms++;
                area = 0;
                dfs(i, j);
                if (area>max_area)
                    max_area = area;
            }
    printf("%d\n%d\n", rooms, max_area);
    return 0;
}