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 solve(vector<vector<char> >& grid) {
        int count = 0;
        // write code here
        vector<vector<int>> search(grid.size(),vector<int> (grid[0].size(),false));
        for(int i=0;i<grid.size();i++){
            for(int j=0;j<grid[0].size();j++){
                if(search[i][j]==1 || grid[i][j] == '0'){
                    search[i][j] = 1;
                    continue;
                }
                
                dfs(grid, search, i, j);
                count++;
            }
        }
        
        return count;
    }
    
    void dfs(vector<vector<char> >& grid,vector<vector<int> >& search,int i,int j){
        if(search[i][j] == 1){
            return;
        }
        search[i][j] = 1;
        if(j-1 >= 0 && grid[i][j-1] == '1'){
            dfs(grid, search, i, j-1);
        }
        
        if(i-1 >= 0 && grid[i-1][j] == '1'){
            dfs(grid, search, i-1, j);
        }
        
        if(i+1 < grid.size() && grid[i+1][j] =='1'){
            dfs(grid, search, i+1, j);
        }
        
        if(j+1 < grid[0].size() && grid[i][j+1] == '1'){
            dfs(grid, search, i, j+1);
        }
    }
};