max area of island

Author: weiy

Diff for: Array/FootballFans.py

@@ -11,7 +11,7 @@
 
 类似算法的 leetcode：
 https://leetcode.com/problems/number-of-islands/description/  解答请看 NumberOfIslands.py
-https://leetcode.com/problems/max-area-of-island/description/ 解答请看 
+https://leetcode.com/problems/max-area-of-island/description/ 解答请看 MaxAreaOfIsland.py
 
 """
 

Diff for: Array/MaxAreaOfIsland.py

@@ -0,0 +1,79 @@
+"""
+与今日头条秋招第一题最相似的一道题，只是方向少了四个。
+
+Given a non-empty 2D array grid of 0's and 1's, an island is a group of 1's (representing land) connected 4-directionally (horizontal or vertical.) You may assume all four edges of the grid are surrounded by water.
+
+Find the maximum area of an island in the given 2D array. (If there is no island, the maximum area is 0.)
+
+Example 1:
+[[0,0,1,0,0,0,0,1,0,0,0,0,0],
+ [0,0,0,0,0,0,0,1,1,1,0,0,0],
+ [0,1,1,0,1,0,0,0,0,0,0,0,0],
+ [0,1,0,0,1,1,0,0,1,0,1,0,0],
+ [0,1,0,0,1,1,0,0,1,1,1,0,0],
+ [0,0,0,0,0,0,0,0,0,0,1,0,0],
+ [0,0,0,0,0,0,0,1,1,1,0,0,0],
+ [0,0,0,0,0,0,0,1,1,0,0,0,0]]
+Given the above grid, return 6. Note the answer is not 11, because the island must be connected 4-directionally.
+Example 2:
+[[0,0,0,0,0,0,0,0]]
+Given the above grid, return 0.
+Note: The length of each dimension in the given grid does not exceed 50.
+
+passed:
+beat 54%.
+
+测试地址：
+https://leetcode.com/problems/max-area-of-island/description/
+
+"""
+
+class Solution(object):
+    def makeAroundXY(self, x, y):
+        return ((x, y-1),
+                (x, y+1),
+                (x-1, y),
+                (x+1, y))
+    
+    def maxAreaOfIsland(self, court):
+        """
+        :type grid: List[List[str]]
+        :rtype: int
+        """
+        fans_groups = []
+        x = 0
+        y = 0
+        if not court:
+            return 0
+        
+        x_length = len(court[0])
+        y_length = len(court)
+
+        def helper(x, y, result=0):
+            Xy = self.makeAroundXY(x, y)
+            for i in Xy:
+                try:
+                    if i[0] < 0 or i[1] < 0:
+                        continue
+
+                    if court[i[1]][i[0]] == 1:
+                        court[i[1]][i[0]] = 0
+                        result += 1
+                        t = helper(i[0], i[1], 0)
+                        result += t
+                except IndexError:
+                    continue
+            else:
+                return result
+
+
+        for y in range(y_length):
+            for x in range(x_length):
+                if court[y][x] == 1:
+                    court[y][x] = 0
+                    fans_groups.append(helper(x, y, 1))
+
+        if not fans_groups:
+            return 0
+
+        return max(fans_groups)