题目链接 acwing 1098.城堡问题

求大佬解答为啥

int dx[4] = {0, -1, 0, 1}, dy[4] = {-1, 0, 1, 0};
//int dx[4] = {0, 0, 1, -1}, dy[4] = {1, -1, 0, 0};

我换成下面那个就不对了

错误的代码：

// 用二进制表示的状态， 太强了，以后看到 1 2 4 8 要引起注意

#include<iostream>
#include<queue>
#include<algorithm>
#include<cstring>

#define x first
#define y second

using namespace std;
typedef pair<int ,int> PII;
const int N = 60;
bool yin[N][N];
int g[N][N];
int n, m;
int dx[4] = {0, -1, 0, 1}, dy[4] = {-1, 0, 1, 0};
//int dx[4] = {0, 0, 1, -1}, dy[4] = {1, -1, 0, 0};
queue<PII> q;

int bfs(int a, int b)
{
    q.push({a, b});
    int area = 0;
    yin[a][b] = true;

    while(q.size())
    {
        auto t = q.front();
        q.pop();
        area ++;
        for(int i = 0; i < 4; i ++)
        {
            int sx = t.x + dx[i], sy = t.y + dy[i];
            if(sx >= n || sx < 0 || sy >= m || sy < 0 || yin[sx][sy]) continue;
            if(g[t.x][t.y] >> i & 1) continue;

            yin[sx][sy] = true;
            q.push({sx, sy});
        }

    }
    return area;
}

int main()
{
    cin >> n >> m;
    for(int i = 0; i < n; i ++)
        for(int j = 0; j < m; j ++)
            cin >> g[i][j];

    int cnt = 0, ares = 0;
    for(int i = 0; i < n; i ++)
        for(int j = 0; j < m; j ++)
        {
            if(!yin[i][j])
            {
                ares = max (ares, bfs(i, j));
                yin[i][j] = true;
                cnt ++;
            }
        }

    cout << cnt << endl;
    cout << ares << endl;
    return 0;
}

不知道为啥错了

提问于17天前

no_one

10967