print_foobar_alternately.py (1406B)
| # 1115. Print FooBar Alternately
from threading import Semaphore
"""
suppose you are given the following code:
class FooBar {
public void foo() {
for (int i = 0; i < n; i++) {
print("foo");
}
}
public void bar() {
for (int i = 0; i < n; i++) {
print("bar");
}
}
}
the same instance of 'FooBar' will be passed to two different threads: thread
'a' will call 'foo()' and thread 'b' will call 'bar()'. modify the given
program to output "foobar" 'n' times.
"""
def printFoo():
print("foo")
def printBar():
print("bar")
class FooBar(object):
def __init__(self, n):
self.n = n
self.s_foo = Semaphore(1)
self.s_bar = Semaphore(0)
def foo(self, printFoo):
"""
:type printFoo: method
:rtype: void
"""
for i in range(self.n):
self.s_foo.acquire()
# printFoo() outputs "foo". Do not change or remove this line.
printFoo()
self.s_bar.release()
def bar(self, printBar):
"""
:type printBar: method
:rtype: void
"""
for i in range(self.n):
self.s_bar.acquire()
# printBar() outputs "bar". Do not change or remove this line.
printBar()
self.s_foo.release()
if __name__ == "__main__":
f1 = FooBar(1)
f2 = FooBar(2)
f1.foo()
f1.bar()
f2.foo()
f2.bar()
|
