Print FooBar Alternately
<p>Suppose you are given the following code:</p>

<pre>
class FooBar {
  public void foo() {
    for (int i = 0; i &lt; n; i++) {
      print(&quot;foo&quot;);
    }
  }

  public void bar() {
    for (int i = 0; i &lt; n; i++) {
      print(&quot;bar&quot;);
    }
  }
}
</pre>

<p>The same instance of <code>FooBar</code> will be passed to two different threads:</p>

<ul>
	<li>thread <code>A</code> will call <code>foo()</code>, while</li>
	<li>thread <code>B</code> will call <code>bar()</code>.</li>
</ul>

<p>Modify the given program to output <code>&quot;foobar&quot;</code> <code>n</code> times.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> n = 1
<strong>Output:</strong> &quot;foobar&quot;
<strong>Explanation:</strong> There are two threads being fired asynchronously. One of them calls foo(), while the other calls bar().
&quot;foobar&quot; is being output 1 time.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> n = 2
<strong>Output:</strong> &quot;foobarfoobar&quot;
<strong>Explanation:</strong> &quot;foobar&quot; is being output 2 times.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= n &lt;= 1000</code></li>
</ul>

['print-in-order', 'print-zero-even-odd']
[]
[{"value": "cpp", "text": "C++", "defaultCode": "class FooBar {\nprivate:\n    int n;\n\npublic:\n    FooBar(int n) {\n        this->n = n;\n    }\n\n    void foo(function<void()> printFoo) {\n        \n        for (int i = 0; i < n; i++) {\n            \n        \t// printFoo() outputs \"foo\". Do not change or remove this line.\n        \tprintFoo();\n        }\n    }\n\n    void bar(function<void()> printBar) {\n        \n        for (int i = 0; i < n; i++) {\n            \n        \t// printBar() outputs \"bar\". Do not change or remove this line.\n        \tprintBar();\n        }\n    }\n};"}, {"value": "java", "text": "Java", "defaultCode": "class FooBar {\n    private int n;\n\n    public FooBar(int n) {\n        this.n = n;\n    }\n\n    public void foo(Runnable printFoo) throws InterruptedException {\n        \n        for (int i = 0; i < n; i++) {\n            \n        \t// printFoo.run() outputs \"foo\". Do not change or remove this line.\n        \tprintFoo.run();\n        }\n    }\n\n    public void bar(Runnable printBar) throws InterruptedException {\n        \n        for (int i = 0; i < n; i++) {\n            \n            // printBar.run() outputs \"bar\". Do not change or remove this line.\n        \tprintBar.run();\n        }\n    }\n}"}, {"value": "python", "text": "Python", "defaultCode": "class FooBar(object):\n    def __init__(self, n):\n        self.n = n\n\n\n    def foo(self, printFoo):\n        \"\"\"\n        :type printFoo: method\n        :rtype: void\n        \"\"\"\n        for i in xrange(self.n):\n            \n            # printFoo() outputs \"foo\". Do not change or remove this line.\n        \tprintFoo()\n\n\n    def bar(self, printBar):\n        \"\"\"\n        :type printBar: method\n        :rtype: void\n        \"\"\"\n        for i in xrange(self.n):\n            \n            # printBar() outputs \"bar\". Do not change or remove this line.\n        \tprintBar()"}, {"value": "python3", "text": "Python3", "defaultCode": "class FooBar:\n    def __init__(self, n):\n        self.n = n\n\n\n    def foo(self, printFoo: 'Callable[[], None]') -> None:\n        \n        for i in range(self.n):\n            \n            # printFoo() outputs \"foo\". Do not change or remove this line.\n        \tprintFoo()\n\n\n    def bar(self, printBar: 'Callable[[], None]') -> None:\n        \n        for i in range(self.n):\n            \n            # printBar() outputs \"bar\". Do not change or remove this line.\n        \tprintBar()"}, {"value": "c", "text": "C", "defaultCode": "typedef struct {\n    int n;\n} FooBar;\n\n// Function declarations. Do not change or remove this line\nvoid printFoo();\nvoid printBar();\n\nFooBar* fooBarCreate(int n) {\n    FooBar* obj = (FooBar*) malloc(sizeof(FooBar));\n    obj->n = n;\n    return obj;\n}\n\nvoid foo(FooBar* obj) {\n    \n    for (int i = 0; i < obj->n; i++) {\n        \n        // printFoo() outputs \"foo\". Do not change or remove this line.\n        printFoo();\n    }\n}\n\nvoid bar(FooBar* obj) {\n    \n    for (int i = 0; i < obj->n; i++) {\n        \n        // printBar() outputs \"bar\". Do not change or remove this line.\n        printBar();\n    }\n}\n\nvoid fooBarFree(FooBar* obj) {\n    \n}"}, {"value": "csharp", "text": "C#", "defaultCode": "public class FooBar {\n    private int n;\n\n    public FooBar(int n) {\n        this.n = n;\n    }\n\n    public void Foo(Action printFoo) {\n        \n        for (int i = 0; i < n; i++) {\n            \n        \t// printFoo() outputs \"foo\". Do not change or remove this line.\n        \tprintFoo();\n        }\n    }\n\n    public void Bar(Action printBar) {\n        \n        for (int i = 0; i < n; i++) {\n            \n            // printBar() outputs \"bar\". Do not change or remove this line.\n        \tprintBar();\n        }\n    }\n}"}, {"value": "golang", "text": "Go", "defaultCode": "type FooBar struct {\n\tn int\n}\n\nfunc NewFooBar(n int) *FooBar {\n\treturn &FooBar{n: n}\n}\n\nfunc (fb *FooBar) Foo(printFoo func()) {\n\tfor i := 0; i < fb.n; i++ {\n\t\t// printFoo() outputs \"foo\". Do not change or remove this line.\n        printFoo()\n\t}\n}\n\nfunc (fb *FooBar) Bar(printBar func()) {\n\tfor i := 0; i < fb.n; i++ {\n\t\t// printBar() outputs \"bar\". Do not change or remove this line.\n        printBar()\n\t}\n}"}]
{
  "name": "FooBar",
  "params": [
    {
      "name": "n",
      "type": "integer"
    }
  ],
  "return": {
    "type": "integer"
  },
  "languages": [
    "java",
    "cpp",
    "python",
    "c",
    "python3",
    "csharp",
    "golang"
  ],
  "manual": true
}
{"cpp": ["C++", "<p>Compiled with <code> clang 19 </code> using the latest C++ 23 standard, and <code>libstdc++</code> provided by GCC 14.</p>\r\n\r\n<p>Your code is compiled with level two optimization (<code>-O2</code>). <a href=\"https://github.com/google/sanitizers/wiki/AddressSanitizer\" target=\"_blank\">AddressSanitizer</a> is also enabled to help detect out-of-bounds and use-after-free bugs.</p>\r\n\r\n<p>Most standard library headers are already included automatically for your convenience.</p>"], "java": ["Java", "<p><code>OpenJDK 21</code>. Using compile arguments: <code>--enable-preview --release 21</code></p>\r\n\r\n<p>Most standard library headers are already included automatically for your convenience.</p>\r\n<p>Includes <code>Pair</code> class from https://docs.oracle.com/javase/8/javafx/api/javafx/util/Pair.html.</p>"], "python": ["Python", "<p><code>Python 2.7.18</code>.</p>\r\n\r\n<p>Most libraries are already imported automatically for your convenience, such as <a href=\"https://docs.python.org/2/library/array.html\" target=\"_blank\">array</a>, <a href=\"https://docs.python.org/2/library/bisect.html\" target=\"_blank\">bisect</a>, <a href=\"https://docs.python.org/2/library/collections.html\" target=\"_blank\">collections</a>. If you need more libraries, you can import it yourself.</p>\r\n\r\n<p>For Map/TreeMap data structure, you may use <a href=\"http://www.grantjenks.com/docs/sortedcontainers/\" target=\"_blank\">sortedcontainers</a> library.</p>\r\n\r\n<p>Note that Python 2.7 <a href=\"https://www.python.org/dev/peps/pep-0373/\" target=\"_blank\">is not maintained anymore</a>. For the latest Python, please choose Python3 instead.</p>"], "c": ["C", "<p>Compiled with <code>gcc 14</code> using the gnu11 standard.</p>\r\n\r\n<p>Your code is compiled with level one optimization (<code>-O2</code>). <a href=\"https://github.com/google/sanitizers/wiki/AddressSanitizer\" target=\"_blank\">AddressSanitizer</a> is also enabled to help detect out-of-bounds and use-after-free bugs.</p>\r\n\r\n<p>Most standard library headers are already included automatically for your convenience.</p>\r\n\r\n<p>For hash table operations, you may use <a href=\"https://troydhanson.github.io/uthash/\" target=\"_blank\">uthash</a>. \"uthash.h\" is included by default. Below are some examples:</p>\r\n\r\n<p><b>1. Adding an item to a hash.</b>\r\n<pre>\r\nstruct hash_entry {\r\n    int id;            /* we'll use this field as the key */\r\n    char name[10];\r\n    UT_hash_handle hh; /* makes this structure hashable */\r\n};\r\n\r\nstruct hash_entry *users = NULL;\r\n\r\nvoid add_user(struct hash_entry *s) {\r\n    HASH_ADD_INT(users, id, s);\r\n}\r\n</pre>\r\n</p>\r\n\r\n<p><b>2. Looking up an item in a hash:</b>\r\n<pre>\r\nstruct hash_entry *find_user(int user_id) {\r\n    struct hash_entry *s;\r\n    HASH_FIND_INT(users, &user_id, s);\r\n    return s;\r\n}\r\n</pre>\r\n</p>\r\n\r\n<p><b>3. Deleting an item in a hash:</b>\r\n<pre>\r\nvoid delete_user(struct hash_entry *user) {\r\n    HASH_DEL(users, user);  \r\n}\r\n</pre>\r\n</p>"], "csharp": ["C#", "<p><a href=\"https://learn.microsoft.com/en-us/dotnet/csharp/whats-new/csharp-13\" target=\"_blank\">C# 13</a> with .NET 9 runtime</p>"], "golang": ["Go", "<p><code>Go 1.23</code></p>\r\n<p>Support <a href=\"https://pkg.go.dev/github.com/emirpasic/gods@v1.18.1\" target=\"_blank\">https://pkg.go.dev/github.com/emirpasic/gods@v1.18.1</a> and <a href=\"https://pkg.go.dev/github.com/emirpasic/gods/v2@v2.0.0-alpha\" target=\"_blank\">https://pkg.go.dev/github.com/emirpasic/gods/v2@v2.0.0-alpha</a> library.</p>"], "python3": ["Python3", "<p><code>Python 3.11</code>.</p>\r\n\r\n<p>Most libraries are already imported automatically for your convenience, such as <a href=\"https://docs.python.org/3/library/array.html\" target=\"_blank\">array</a>, <a href=\"https://docs.python.org/3/library/bisect.html\" target=\"_blank\">bisect</a>, <a href=\"https://docs.python.org/3/library/collections.html\" target=\"_blank\">collections</a>. If you need more libraries, you can import it yourself.</p>\r\n\r\n<p>For Map/TreeMap data structure, you may use <a href=\"http://www.grantjenks.com/docs/sortedcontainers/\" target=\"_blank\">sortedcontainers</a> library.</p>"]}
['Concurrency']