day 17

Author: Your Name

138CopyListwithRandomPointer.py

@@ -0,0 +1,60 @@
+
+# Definition for a Node.
+class Node:
+    def __init__(self, x, next=None, random=None):
+        self.val = int(x)
+        self.next = next
+        self.random = random
+
+
+class Solution(object):
+    def copyRandomList(self, head):
+        """
+        :type head: Node
+        :rtype: Node
+        [[3,null],[2,0],[1,null]]
+        """
+        
+        cacheMap = {}
+        
+        curr = head 
+        newCurr = None
+        last = None
+        newHead = None
+        while curr:
+            val = curr.val
+            newCurr = Node(val)
+            if last:
+                last.next = newCurr
+            else:
+                newHead = newCurr
+            cacheMap[curr] = newCurr
+            last = newCurr
+            curr = curr.next
+        
+        curr = head
+        newCurr = newHead
+        while curr:
+            random = curr.random
+            mirrorRandom = None
+            if random:
+                mirrorRandom = cacheMap[random]
+            newCurr.random = mirrorRandom
+            
+            curr = curr.next
+            newCurr = newCurr.next
+        return newHead
+
+
+a = Node(3)
+b = Node(2)
+c = Node(1)
+
+a.next = b
+b.next = c 
+b.random = a 
+
+sol = Solution()
+res = sol.copyRandomList(a)
+print(res)
+        

207.CourseSchedule.py

@@ -0,0 +1,9 @@
+class Solution(object):
+    def canFinish(self, numCourses, prerequisites):
+        """
+        :type numCourses: int
+        :type prerequisites: List[List[int]]
+        :rtype: bool
+        [[1,0],[0,1]]
+        """
+