1115-print-foobar-alternately

Try it on leetcode

Description

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(), while
• thread B will call bar().

Modify the given program to output "foobar" n times.

 

Example 1:

Input: n = 1
Output: "foobar"
Explanation: There are two threads being fired asynchronously. One of them calls foo(), while the other calls bar().
"foobar" is being output 1 time.

Example 2:

Input: n = 2
Output: "foobarfoobar"
Explanation: "foobar" is being output 2 times.

 

Constraints:

• 1 <= n <= 1000

Solution(Python)

from threading import Barrier


class FooBar:
    def __init__(self, n):
        self.n = n
        self.barrier = Barrier(2)

    def foo(self, printFoo):
        for i in range(self.n):
            printFoo()
            self.barrier.wait()

    def bar(self, printBar):
        for i in range(self.n):
            self.barrier.wait()
            printBar()