题解 | #岛屿数量#

    public int solve (char[][] grid) {
        int count = 0;
        for(int i = 0; i<grid.length; i++){
            for(int j = 0; j<grid[0].length; j++){
                if(grid[i][j] == '1'){
                    count++;
                    dfs(grid,i,j);
                }
            }
        }
        return count;
    }
    public void dfs(char[][] grid, int i, int j){
        if(i<0||j<0||i>=grid.length||j>=grid[0].length) return;
        if(grid[i][j] == '1'){
            grid[i][j] = '0';
            dfs(grid,i+1,j);
            dfs(grid,i,j+1);
            dfs(grid,i-1,j);
            dfs(grid,i,j-1);
        }
    }