2019-05-27

0302.包含全部黑色像素的最小矩形/0302-包含全部黑色像素的最小矩形.py

@@ -0,0 +1,37 @@
+class Solution(object):
+    def minArea(self, image, x, y):
+        """
+        :type image: List[List[str]]
+        :type x: int
+        :type y: int
+        :rtype: int
+        """
+        m, n = len(image), len(image[0])
+        visited = [[0 for _ in range(n + 1)] for _ in range(m + 1)]
+
+        dx = [1, -1, 0, 0]
+        dy = [0, 0, 1, -1]
+        self.min_x, self.min_y, self.max_x, self.max_y = 0, 0, 0, 0
+
+        def dfs(x0, y0):
+            # print (self.min_x, self.min_y, self.max_x, self.max_y, x0, y0)
+            self.min_x = min(self.min_x, x0)  
+            self.max_x = max(self.max_x, x0)
+            self.min_y = min(self.min_y, y0)  
+            self.max_y = max(self.max_y, y0)
+            visited[x0][y0] = 1
+
+            for k in range(4):
+                x = x0 + dx[k]
+                y = y0 + dy[k]
+
+                if 0 <= x < m and 0 <= y < n and visited[x][y] == 0 and image[x][y] == "1":
+                    dfs(x, y)
+
+        for i in range(m):
+            for j in range(n):
+                if image[i][j] == "1":
+                    self.min_x, self.min_y, self.max_x, self.max_y = i, j, i, j
+                    dfs(i, j) #因为全部相连，所以一次主体DFS之后就可以返回
+                    # print (self.min_x, self.min_y, self.max_x, self.max_y)        
+                    return (self.max_x - self.min_x + 1) * (self.max_y - self.min_y + 1)