Create 1254. Number of Closed Islands 6 apr (#140)

Author: Chayandas07

1254. Number of Closed Islands 6 apr

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+class Solution {
+public:
+    int closedIsland(vector<vector<int>>& g) {
+        queue<pair<int,int>>q;
+        int n=g.size(),m=g[0].size();
+        for(int i=0;i<n;i++){
+            for(int j=0;j<m;j++){
+                if(i==0 || i==n-1 || j==0 || j==m-1){
+                    if(g[i][j]==0){
+                    g[i][j]=1;
+                    q.push({i,j});}
+                }
+            }
+        }
+        while(q.size()){
+            auto l=q.front();
+            q.pop();
+            int x=l.first;
+            int y=l.second;
+            int dx[4]={1,-1,0,0};
+            int dy[4]={0,0,1,-1};
+            for(int i=0;i<4;i++){
+                int nx=dx[i]+x;
+                int ny=dy[i]+y;
+                if(nx>=0 && nx<n && ny>=0 && ny<m && g[nx][ny]==0){
+                    g[nx][ny]=1;
+                    q.push({nx,ny});
+                }
+            }
+        }
+        int ct=0;
+        for(int i=0;i<n;i++){
+            for(int j=0;j<m;j++){
+                if(!g[i][j]){
+                    ct++;
+                      q.push({i,j});
+                       while(q.size()){
+            auto l=q.front();
+            q.pop();
+            int x=l.first;
+            int y=l.second;
+            int dx[4]={1,-1,0,0};
+            int dy[4]={0,0,1,-1};
+            for(int i=0;i<4;i++){
+                int nx=dx[i]+x;
+                int ny=dy[i]+y;
+                if(nx>=0 && nx<n && ny>=0 && ny<m && g[nx][ny]==0){
+                    g[nx][ny]=1;
+                    q.push({nx,ny});
+                }
+            }
+        }
+                }
+            }
+        }
+        return ct;
+    }
+};