题解 | #岛屿数量#

class Solution {
public:
    /**
     * 判断岛屿数量
     * @param grid char字符型vector<vector<>> 
     * @return int整型
     */
    int nums;
    vector<vector<char> > grid;
    void dfs(int x,int y){
        grid[x][y]='0';
        if(x+1<grid.size()&&grid[x+1][y]=='1'){
            dfs(x+1,y);
        }
        if(x-1>=0&&grid[x-1][y]=='1'){
            dfs(x-1,y);
        }
        if(y+1<grid[0].size()&&grid[x][y+1]=='1'){
            dfs(x,y+1);
        }
        if(y-1>=0&&grid[x][y-1]=='1'){
            dfs(x,y-1);
        }
    }
    int solve(vector<vector<char> >& _grid) {
        nums=0;
        if(_grid.size()==0) return nums;
        this->grid=_grid;

        for(int i=0;i<grid.size();i++){
            for(int j=0;j<grid[0].size();j++){
                if(grid[i][j]=='1'){
                    dfs(i,j);
                    nums++;
                }
            }
        }
        return nums;
    }
};