add new solutions

solutions/11/q1115/solution.go

@@ -0,0 +1,36 @@
+package q1115
+
+type FooBar struct {
+	n        int
+	foo, bar chan struct{}
+}
+
+func NewFooBar(n int) *FooBar {
+	ret := &FooBar{
+		n:   n,
+		foo: make(chan struct{}, 1),
+		bar: make(chan struct{}, 1),
+	}
+	ret.bar <- struct{}{}
+	return ret
+}
+
+func (fb *FooBar) Foo(printFoo func()) {
+	for i := 0; i < fb.n; i++ {
+		<-fb.bar
+		// printFoo() outputs "foo". Do not change or remove this line.
+		printFoo()
+
+		fb.foo <- struct{}{}
+	}
+}
+
+func (fb *FooBar) Bar(printBar func()) {
+	for i := 0; i < fb.n; i++ {
+		<-fb.foo
+		// printBar() outputs "bar". Do not change or remove this line.
+		printBar()
+
+		fb.bar <- struct{}{}
+	}
+}