1114. Print in Order.py

Author: keineahnung2345

1114. Print in Order.py

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+//https://leetcode.com/problems/print-in-order/discuss/335939/5-Python-threading-solutions-(Barrier-Lock-Event-Semaphore-Condition)-with-explanation
+
+//Runtime: 28 ms, faster than 96.04% of Python3 online submissions for Print in Order.
+//Memory Usage: 13.1 MB, less than 100.00% of Python3 online submissions for Print in Order.
+
+from threading import Barrier
+
+class Foo:
+    def __init__(self):
+        self.first_barrier = Barrier(2)
+        self.second_barrier = Barrier(2)
+
+    def first(self, printFirst: 'Callable[[], None]') -> None:
+        
+        # printFirst() outputs "first". Do not change or remove this line.
+        printFirst()
+        self.first_barrier.wait()
+
+
+    def second(self, printSecond: 'Callable[[], None]') -> None:
+        self.first_barrier.wait()
+        # printSecond() outputs "second". Do not change or remove this line.
+        printSecond()
+        self.second_barrier.wait()
+
+
+    def third(self, printThird: 'Callable[[], None]') -> None:
+        self.second_barrier.wait()
+        # printThird() outputs "third". Do not change or remove this line.
+        printThird()
+
+//Runtime: 40 ms, faster than 59.25% of Python3 online submissions for Print in Order.
+//Memory Usage: 13.1 MB, less than 100.00% of Python3 online submissions for Print in Order.
+
+from threading import Lock
+
+class Foo:
+    def __init__(self):
+        self.locks = (Lock(), Lock())
+        self.locks[0].acquire()
+        self.locks[1].acquire()
+
+    def first(self, printFirst: 'Callable[[], None]') -> None:
+        
+        # printFirst() outputs "first". Do not change or remove this line.
+        printFirst()
+        self.locks[0].release()
+
+    def second(self, printSecond: 'Callable[[], None]') -> None:
+        
+        # printSecond() outputs "second". Do not change or remove this line.
+        with self.locks[0]:
+            printSecond()
+            self.locks[1].release()
+
+
+    def third(self, printThird: 'Callable[[], None]') -> None:
+        
+        # printThird() outputs "third". Do not change or remove this line.
+        with self.locks[1]:
+            printThird()
+
+//Runtime: 40 ms, faster than 59.25% of Python3 online submissions for Print in Order.
+//Memory Usage: 13.1 MB, less than 100.00% of Python3 online submissions for Print in Order.
+
+from threading import Event
+
+class Foo:
+    def __init__(self):
+        self.done = (Event(), Event())
+
+    def first(self, printFirst: 'Callable[[], None]') -> None:
+        
+        # printFirst() outputs "first". Do not change or remove this line.
+        printFirst()
+        self.done[0].set()
+
+
+    def second(self, printSecond: 'Callable[[], None]') -> None:
+        
+        # printSecond() outputs "second". Do not change or remove this line.
+        self.done[0].wait()
+        printSecond()
+        self.done[1].set()
+
+
+    def third(self, printThird: 'Callable[[], None]') -> None:
+        
+        # printThird() outputs "third". Do not change or remove this line.
+        self.done[1].wait()
+        printThird()
+
+/Runtime: 44 ms, faster than 44.53% of Python3 online submissions for Print in Order.
+//Memory Usage: 13 MB, less than 100.00% of Python3 online submissions for Print in Order.
+
+from threading import Semaphore
+
+class Foo:
+    def __init__(self):
+        self.gates = (Semaphore(0), Semaphore(0))
+
+
+    def first(self, printFirst: 'Callable[[], None]') -> None:
+        
+        # printFirst() outputs "first". Do not change or remove this line.
+        printFirst()
+        self.gates[0].release()
+
+
+    def second(self, printSecond: 'Callable[[], None]') -> None:
+        
+        # printSecond() outputs "second". Do not change or remove this line.
+        with self.gates[0]:
+            printSecond()
+            self.gates[1].release()
+
+
+    def third(self, printThird: 'Callable[[], None]') -> None:
+        
+        # printThird() outputs "third". Do not change or remove this line.
+        with self.gates[1]:
+            printThird()
+
+//Runtime: 44 ms, faster than 44.53% of Python3 online submissions for Print in Order.
+//Memory Usage: 13 MB, less than 100.00% of Python3 online submissions for Print in Order.
+
+from threading import Condition
+
+class Foo:
+    def __init__(self):
+        self.exec_condition = Condition()
+        self.order = 0
+        self.first_finish = lambda : self.order == 1
+        self.second_finish = lambda : self.order == 2
+
+    def first(self, printFirst: 'Callable[[], None]') -> None:
+        
+        # printFirst() outputs "first". Do not change or remove this line.
+        with self.exec_condition:
+            printFirst()
+            self.order = 1
+            self.exec_condition.notify(2)
+
+
+    def second(self, printSecond: 'Callable[[], None]') -> None:
+        
+        # printSecond() outputs "second". Do not change or remove this line.
+        with self.exec_condition:
+            self.exec_condition.wait_for(self.first_finish)
+            printSecond()
+            self.order = 2
+            self.exec_condition.notify()
+
+
+    def third(self, printThird: 'Callable[[], None]') -> None:
+        
+        # printThird() outputs "third". Do not change or remove this line.
+        with self.exec_condition:
+            self.exec_condition.wait_for(self.second_finish)
+            printThird()