#include <iostream>
#include <vector>
#include <queue>
#include <list>
using namespace std;
int dir[4][2] = { 0,1,1,0,-1,0,0,-1 };
int count;
void dfs(vector<vector<int>>& grid, int x, int y)
{
grid[x][y] = 0;
count++;
for (int i = 0; i < 4; i++)
{
int nextx = x + dir[i][0];
int nexty = y + dir[i][1];
//超过边界不考虑
if (nextx < 0 || nextx >= grid.size() || nexty < 0 || nexty >= grid[0].size())continue;
if (grid[nextx][nexty] == 0)continue;
dfs(grid, nextx, nexty);
}
}
int main()
{
int n, m;
cin >> n >> m;
vector<vector<int>> grid(n, vector<int>(m, 0));
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
cin >> grid[i][j];
}
}
for (int i = 0; i < n; i++)
{
if (grid[i][0] == 1)dfs(grid, i, 0);
if (grid[i][m - 1] == 1)dfs(grid, i, m - 1);
}
for (int i = 0; i < m; i++)
{
if (grid[0][i] == 1)dfs(grid, 0, i);
if (grid[n - 1][i] == 1)dfs(grid, n - 1, i);
}
count = 0;
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
if (grid[i][j] == 1)dfs(grid, i, j);
}
}
cout << count << endl;
}
#include <iostream>
#include <vector>
#include <queue>
#include <list>
using namespace std;
int dir[4][2] = { 0,1,1,0,-1,0,0,-1 };
void dfs(vector<vector<int>>& grid, int x, int y)
{
grid[x][y] = 2;
for (int i = 0; i < 4; i++)
{
int nextx = x + dir[i][0];
int nexty = y + dir[i][1];
//超过边界不考虑
if (nextx < 0 || nextx >= grid.size() || nexty < 0 || nexty >= grid[0].size())continue;
if (grid[nextx][nexty] == 0||grid[nextx][nexty]==2)continue;
dfs(grid, nextx, nexty);
}
}
int main()
{
int n, m;
cin >> n >> m;
vector<vector<int>> grid(n, vector<int>(m, 0));
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
cin >> grid[i][j];
}
}
for (int i = 0; i < n; i++)
{
if (grid[i][0] == 1)dfs(grid, i, 0);
if (grid[i][m - 1] == 1)dfs(grid, i, m - 1);
}
for (int i = 0; i < m; i++)
{
if (grid[0][i] == 1)dfs(grid, 0, i);
if (grid[n - 1][i] == 1)dfs(grid, n - 1, i);
}
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
if (grid[i][j] == 1)grid[i][j]=0;
if (grid[i][j] == 2)grid[i][j] = 1;
}
}
for (int i = 0; i < n; i++)
{
for (int j = 0; j < m; j++)
{
cout << grid[i][j] << " ";
}
cout << endl;
}
}