959. Regions Cut By Slashes

题目来源：959. Regions Cut By Slashes  

https://leetcode.com/problems/regions-cut-by-slashes/

 自我感觉难度/真实难度：             写题时间时长：

 题意：

 分析：思路就是把每一个符号位置，扩展成3*3的小格子，然后把自己的边界设为1就可以了，最后使用数区域的方法就可以了，DFS一下，看有多少区域

 自己的代码：

import numpy
class Solution(object):
    def regionsBySlashes(self, g):
        """
        :type grid: List[str]
        :rtype: int
        """
        self.l=len(g)*3
        count=0
        b=numpy.zeros((self.l,self.l))
        for i in range(self.l/3):
            for j in range(self.l/3):
                if g[i][j] == '/':
                    b[i * 3][j * 3 + 2] = b[i * 3 + 1][j * 3 + 1] = b[i * 3 + 2][j * 3] = 1 
                if g[i][j] == '\':
                    b[i * 3][j * 3] = b[i * 3 + 1][j * 3 + 1] = b[i * 3 + 2][j * 3 + 2] = 1;
        for i in range(self.l):
            for j in range(self.l):
                if b[i][j]==0:
                    count+=1
                    self.one(i,j,b)
        return count
    
    def one(self,x,y,a):
        left_x=x-1
        right_x=x+1
        up_y=y-1
        down_y=y+1
        if 0<=x<self.l and 0<=y<self.l and a[x,y]==0:
            a[x][y]=1
            self.one(left_x,y,a)
            self.one(right_x,y,a)
            self.one(x,up_y,a)
            self.one(x,down_y,a)
        else:
            return 
            
        
            

代码还是要讲求简介

 

代码效率/结果：

 优秀代码：

class Solution(object):
    def regionsBySlashes(self, grid):
        """
        :type grid: List[str]
        :rtype: int
        """
        # colors = [down, right]
        N = len(grid)
        mapping = collections.defaultdict(set)
        colors = [[i,0] for i in xrange(N)]
        color = N-1
        for row in grid:
#            print colors, row
            for i, ch in enumerate(row):
                if i > 0:
                    right = colors[i-1][1] 
                else:
                    color += 1
                    right = color
                down = colors[i][0]
#                print i, ch, right, down
                if ch == ' ':
                    if right != down:
                        mapping[right].add(down)
                        mapping[ down].add(right)
                    colors[i] = [down, down]
                elif ch == '/':
                    if right != down:
                        mapping[right].add(down)
                        mapping[ down].add(right)
                    color += 1
                    colors[i] = [color, color]
                else:
                    colors[i] = [right, down]       
        
#        print colors

        color += 1
#        print color, mapping
        visited, count = [False] * color, 0
        for item in xrange(color):
            if visited[item]: continue
            count += 1
            level, visited[item] = [item], True
            while level:
                co = level.pop()
                for c in mapping[co]:
                    if not visited[c]:
                        level.append(c)
                        visited[c] = True
        
        return count
            

44m

但是目前还没有看懂这么写出来的

代码效率/结果：

 自己优化后的代码：

 反思改进策略：