2019-08-22

Author: JiayangWu

0256.粉刷房子/0256-粉刷房子.py

@@ -6,12 +6,8 @@ def minCost(self, costs):
         """
         if not costs:
             return 0
-        dp = costs
         for i in range(1, len(costs)):
-            dp[i][0] += min(dp[i - 1][1], dp[i - 1][2])
-            dp[i][1] += min(dp[i - 1][0], dp[i - 1][2])
-            dp[i][2] += min(dp[i - 1][0], dp[i - 1][1])
-        return min(dp[-1])
-            
-                
-                
+            costs[i][0] += min(costs[i - 1][1], costs[i - 1][2])
+            costs[i][1] += min(costs[i - 1][0], costs[i - 1][2])
+            costs[i][2] += min(costs[i - 1][0], costs[i - 1][1])
+        return min(costs[-1])

0257.二叉树的所有路径/0257-二叉树的所有路径.py

@@ -12,30 +12,18 @@ def binaryTreePaths(self, root):
         :rtype: List[str]
         """
         if not root:
-            return list()
-        
-        res = list()
-        temp_res = str(root.val)
-        
+          return []
         if not root.left and not root.right:
-            return [temp_res]
-        
-        self.generate(root.left, str(root.val), res)
-        self.generate(root.right, str(root.val), res)
-        
-        return res
-    
-    def generate(self, node, temp_res, res):
-        if not node:
-            return
-        temp_res += "->" + str(node.val)
-        
-        if not node.left and not node.right:
-            res.append(temp_res)
-            return
-        else:           
-            self.generate(node.left, temp_res, res)
-            self.generate(node.right, temp_res, res)
-            
-        return 
-        
+          return [str(root.val)]
+        self.res = []
+        def dfs(node, tmp):
+          if not node:
+            return 
+          if not node.left and not node.right:
+            self.res.append(tmp + "->" + str(node.val))
+          dfs(node.left, tmp + "->" + str(node.val))
+          dfs(node.right, tmp + "->" + str(node.val))
+          
+        dfs(root.left, str(root.val))
+        dfs(root.right, str(root.val))
+        return self.res