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力扣：200岛屿数量

class Solution {

    int dirs[4][2] = {{0,-1},{0,1},{1,0},{-1,0}};

public:

    int numIslands(vector>& grid) {

        int n = grid.size();

        int m = grid[0].size();

        int res = 0;

        for(int i = 0;i

        {

            for(int j = 0;j

            {

                if(grid[i][j] == '1')

                {

                    res++;

                    grid[i][j] = '0';

                    queue> q;

                    q.push({i,j});

                    while(!q.empty())

                    {

                        auto cell = q.front();

                        q.pop();

                        int r = cell.first;

                        int c = cell.second;

                        for(int i = 0;i<4;i++)

                        {

                            int X = r+dirs[i][0];

                            int Y = c+dirs[i][1];

                            if(X>=0 && X=0 && Y

                            {

                                q.push({X,Y});

                                grid[X][Y] = '0';

                            }

                        }

                    }

                }

            }

        }

        return res;

    }

};