LintCode 433. 岛屿的个数（Number of Islands）

LintCode 433. 岛屿的个数（Number of Islands）

代码：

class Solution:
    """
    @param grid: a boolean 2D matrix
    @return: an integer
    """
    def numIslands(self, grid):
        # write your code here
        n_Islands=0
        n_rows=len(grid)
        if n_rows:
            n_cols=len(grid[0])
        for i in range(n_rows):
            for j in range(n_cols):
                if grid[i][j]==-1 or grid[i][j]==0:
                    continue
                else:
                    self.Islands(grid,i,j,n_rows,n_cols)
                    n_Islands+=1
        return n_Islands

    def Islands(self,grid,i,j,n_rows,n_cols):
        if i<0 or j<0 or i>n_rows-1 or j>n_cols-1:
            return
        elif grid[i][j]==-1 or grid[i][j]==0:
            return
        elif grid[i][j]==1:
            grid[i][j]=-1
            self.Islands(grid,i-1,j,n_rows,n_cols)
            self.Islands(grid,i+1,j,n_rows,n_cols)
            self.Islands(grid,i,j+1,n_rows,n_cols)
            self.Islands(grid,i,j-1,n_rows,n_cols)
            return