1195.fizz-buzz-multithreaded

Statement

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Metadata

• Link: 交替打印字符串
• Difficulty: Medium
• Tag: 多线程

编写一个可以从 1 到 n 输出代表这个数字的字符串的程序，但是：

• 如果这个数字可以被 3 整除，输出 "fizz"。
• 如果这个数字可以被 5 整除，输出 "buzz"。
• 如果这个数字可以同时被 3 和 5 整除，输出 "fizzbuzz"。

例如，当 n = 15，输出： 1, 2, fizz, 4, buzz, fizz, 7, 8, fizz, buzz, 11, fizz, 13, 14, fizzbuzz。

假设有这么一个类：

class FizzBuzz {
  public FizzBuzz(int n) { … }               // constructor
  public void fizz(printFizz) { … }          // only output "fizz"
  public void buzz(printBuzz) { … }          // only output "buzz"
  public void fizzbuzz(printFizzBuzz) { … }  // only output "fizzbuzz"
  public void number(printNumber) { … }      // only output the numbers
}

请你实现一个有四个线程的多线程版  FizzBuzz， 同一个 FizzBuzz 实例会被如下四个线程使用：

1. 线程A将调用 fizz() 来判断是否能被 3 整除，如果可以，则输出 fizz。
2. 线程B将调用 buzz() 来判断是否能被 5 整除，如果可以，则输出 buzz。
3. 线程C将调用 fizzbuzz() 来判断是否同时能被 3 和 5 整除，如果可以，则输出 fizzbuzz。
4. 线程D将调用 number() 来实现输出既不能被 3 整除也不能被 5 整除的数字。

 

提示：

• 本题已经提供了打印字符串的相关方法，如 printFizz() 等，具体方法名请参考答题模板中的注释部分。

 

Metadata

• Link: Fizz Buzz Multithreaded
• Difficulty: Medium
• Tag: Concurrency

You have the four functions:

• printFizz that prints the word "fizz" to the console,
• printBuzz that prints the word "buzz" to the console,
• printFizzBuzz that prints the word "fizzbuzz" to the console, and
• printNumber that prints a given integer to the console.

You are given an instance of the class FizzBuzz that has four functions: fizz, buzz, fizzbuzz and number. The same instance of FizzBuzz will be passed to four different threads:

• Thread A: calls fizz() that should output the word "fizz".
• Thread B: calls buzz() that should output the word "buzz".
• Thread C: calls fizzbuzz() that should output the word "fizzbuzz".
• Thread D: calls number() that should only output the integers.

Modify the given class to output the series [1, 2, "fizz", 4, "buzz", …] where the ith token (1-indexed) of the series is:

• "fizzbuzz" if i is divisible by 3 and 5,
• "fizz" if i is divisible by 3 and not 5,
• "buzz" if i is divisible by 5 and not 3, or
• i if i is not divisible by 3 or 5.

Implement the FizzBuzz class:

• FizzBuzz(int n) Initializes the object with the number n that represents the length of the sequence that should be printed.
• void fizz(printFizz) Calls printFizz to output "fizz".
• void buzz(printBuzz) Calls printBuzz to output "buzz".
• void fizzbuzz(printFizzBuzz) Calls printFizzBuzz to output "fizzbuzz".
• void number(printNumber) Calls printnumber to output the numbers.

 

Example 1:

Input: n = 15
Output: [1,2,"fizz",4,"buzz","fizz",7,8,"fizz","buzz",11,"fizz",13,14,"fizzbuzz"]

Example 2:

Input: n = 5
Output: [1,2,"fizz",4,"buzz"]

 

Constraints:

• 1 <= n <= 50

Solution

C++

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

#define endl "\n"
#define fi first
#define se second
#define all(x) begin(x), end(x)
#define rall rbegin(a), rend(a)
#define bitcnt(x) (__builtin_popcountll(x))
#define complete_unique(a) a.erase(unique(begin(a), end(a)), end(a))
#define mst(x, a) memset(x, a, sizeof(x))
#define MP make_pair

using ll = long long;
using ull = unsigned long long;
using db = double;
using ld = long double;
using VLL = std::vector<ll>;
using VI = std::vector<int>;
using PII = std::pair<int, int>;
using PLL = std::pair<ll, ll>;

using namespace __gnu_pbds;
using namespace std;
template <typename T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

template <typename T, typename S>
inline bool chmax(T &a, const S &b) {
    return a < b ? a = b, 1 : 0;
}

template <typename T, typename S>
inline bool chmin(T &a, const S &b) {
    return a > b ? a = b, 1 : 0;
}

#ifdef LOCAL
#include <debug.hpp>
#else
#define dbg(...)
#endif
// head

class FizzBuzz {
private:
    int n;

public:
    FizzBuzz(int n) {
        this->n = n;
    }

    // printFizz() outputs "fizz".
    void fizz(function<void()> printFizz) {
        while (order_ <= n) {
            if (order_ % 3 != 0 || order_ % 15 == 0) {
                std::this_thread::yield();
                continue;
            } else {
                printFizz();
                order_++;
            }
        }
    }

    // printBuzz() outputs "buzz".
    void buzz(function<void()> printBuzz) {
        while (order_ <= n) {
            if (order_ % 5 != 0 || order_ % 15 == 0) {
                std::this_thread::yield();
                continue;
            } else {
                printBuzz();
                order_++;
            }
        }
    }

    // printFizzBuzz() outputs "fizzbuzz".
    void fizzbuzz(function<void()> printFizzBuzz) {
        while (order_ <= n) {
            if (order_ % 15 != 0) {
                std::this_thread::yield();
                continue;
            } else {
                printFizzBuzz();
                order_++;
            }
        }
    }

    // printNumber(x) outputs "x", where x is an integer.
    void number(function<void(int)> printNumber) {
        for (int i = 1; i <= n; i++) {
            if (i % 3 == 0 || i % 5 == 0) {
                continue;
            }

            while (order_ % 3 == 0 || order_ % 5 == 0) {
                std::this_thread::yield();
            }

            printNumber(i);
            order_++;
        }
    }

private:
    int order_{1};
};

#ifdef LOCAL

int main() {
    return 0;
}

#endif

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最后更新: October 11, 2023