<p>Given a 2D&nbsp;<code>grid</code> consists of <code>0s</code> (land)&nbsp;and <code>1s</code> (water).&nbsp; An <em>island</em> is a maximal 4-directionally connected group of <code><font face="monospace">0</font>s</code> and a <em>closed island</em>&nbsp;is an island <strong>totally</strong>&nbsp;(all left, top, right, bottom) surrounded by <code>1s.</code></p>

<p>Return the number of <em>closed islands</em>.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<p><img alt="" src="https://assets.leetcode.com/uploads/2019/10/31/sample_3_1610.png" style="width: 240px; height: 120px;" /></p>

<pre>
<strong>Input:</strong> grid = [[1,1,1,1,1,1,1,0],[1,0,0,0,0,1,1,0],[1,0,1,0,1,1,1,0],[1,0,0,0,0,1,0,1],[1,1,1,1,1,1,1,0]]
<strong>Output:</strong> 2
<strong>Explanation:</strong> 
Islands in gray are closed because they are completely surrounded by water (group of 1s).</pre>

<p><strong class="example">Example 2:</strong></p>

<p><img alt="" src="https://assets.leetcode.com/uploads/2019/10/31/sample_4_1610.png" style="width: 160px; height: 80px;" /></p>

<pre>
<strong>Input:</strong> grid = [[0,0,1,0,0],[0,1,0,1,0],[0,1,1,1,0]]
<strong>Output:</strong> 1
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> grid = [[1,1,1,1,1,1,1],
&nbsp;              [1,0,0,0,0,0,1],
&nbsp;              [1,0,1,1,1,0,1],
&nbsp;              [1,0,1,0,1,0,1],
&nbsp;              [1,0,1,1,1,0,1],
&nbsp;              [1,0,0,0,0,0,1],
               [1,1,1,1,1,1,1]]
<strong>Output:</strong> 2
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= grid.length, grid[0].length &lt;= 100</code></li>
	<li><code>0 &lt;= grid[i][j] &lt;=1</code></li>
</ul>

class Solution {
public:

    bool count(vector<vector<int>>& grid,int i,int j,vector<vector<bool>>& vis){
        queue<pair<int,int>> q;
        int n=grid.size();
        int m=grid[0].size();

        q.push(make_pair(i,j));
        vis[i][j]=true;

        bool ans=true;

        while(!q.empty()){
            int k=q.front().first;
            int l=q.front().second;
            cout<<k<<" "<<l<<" ";
            q.pop();

            //up
            if(k-1<0)
            ans=false;
            else if(grid[k-1][l]==0&&!vis[k-1][l]){
                q.push(make_pair(k-1,l));
                vis[k-1][l]=true;
            }
            //down
            if(k+1>=n)
                ans=false;
            else if(grid[k+1][l]==0&&!vis[k+1][l]){
                q.push(make_pair(k+1,l));
                vis[k+1][l]=true;
            }

            //right
            if(l+1>=m)
                ans=false;
             else if(grid[k][l+1]==0&&!vis[k][l+1]){
                q.push(make_pair(k,l+1));
                vis[k][l+1]=true;
            }

            //left
            if(l-1<0)
                ans=false;
            else if(grid[k][l-1]==0&&!vis[k][l-1]){
                q.push(make_pair(k,l-1));
                vis[k][l-1]=true;
            }
        }

        return ans;
    }

    int closedIsland(vector<vector<int>>& grid) {
        int n=grid.size();
        int m=grid[0].size();
        int ans=0;
        vector<vector<bool>> vis(n,vector<bool>(m,false));
        for(int i=0;i<n;i++){
            for(int j=0;j<m;j++){
                if(!grid[i][j]&&!vis[i][j]){
                    if(count(grid,i,j,vis))
                        ans++;
                }
            }
        }return ans;
    }
};
17794