// C++ solution code goes here
class Solution {
    public:
      // Function to find distance of nearest 1 in the grid for each cell.
      vector<vector<int>> nearest(vector<vector<int>>& grid) {
          // Code here
          
          int n = grid.size();
          int m = grid[0].size();
          
          vector<vector<int>> vis(n, vector<int>(m,0));
          vector<vector<int>> dist(n, vector<int>(m, 0));
          queue< pair<pair<int,int>, int> > q;
          
          for(int i = 0; i < n; i++)
          {
              for(int j = 0; j < m; j++)
              {
                  if(grid[i][j] == 1)
                  {
                      vis[i][j] = 1;
                      q.push({{i, j}, 0});
                  }
              }
          }
          
          int dr[] = {-1, 0, 1, 0};
          int dc[] = {0, 1, 0, -1};
          
          while(!q.empty())
          {
              int row = q.front().first.first;
              int col = q.front().first.second;
              int dis = q.front().second;
              q.pop();
              dist[row][col] = dis;
              for(int i = 0; i < 4; i++)
              {
                  int nr = row + dr[i];
                  int nc = col + dc[i];
                  
                  if(nr >= 0 && nr < n && nc >= 0 && nc < m && vis[nr][nc] == 0)
                  {
                      vis[nr][nc] = 1;
                      q.push({{nr, nc}, dis + 1});
                  }
              }
          }
          return dist;
      }
  };
        

            // Java solution code goes here
        

        # Python solution code goes here