Fizz Buzz Solutions in C++

// Source : https://leetcode.com/problems/fizz-buzz/
// Author : Hao Chen
// Date   : 2016-11-13



class Solution {
public:
    vector<string> fizzBuzz_old_school_way(int n) {
        vector<string> result;
        for (int i=1; i<=n; i++) {
            if ( i%3 == 0 && i%5 ==0 ) {
                result.push_back("FizzBuzz");
            }else if (i%3 == 0) {
                result.push_back("Fizz");
            }else if (i%5 == 0) {
                result.push_back("Buzz");
            }else{
                result.push_back(std::to_string(i));
            }
        }
        return result;
    }
    
    
    class FizzBuzz {
        public:
            FizzBuzz() : x(0) {}
            
            string operator()() {
                x++; 
                if ( x%3 == 0 && x%5 ==0 ) {
                    return ("FizzBuzz");
                }else if (x%3 == 0) {
                    return ("Fizz");
                }else if (x%5 == 0) {
                    return("Buzz");
                }
                return std::to_string(x);
            }
            
        private:
            int x;
    };
    
    vector<string> fizzBuzz_cpp_way(int n) {
        vector<string> result(n);
        generate(result.begin(), result.end(), FizzBuzz());
        return result;
    }
    
    vector<string> fizzBuzz(int n) {
        
        //both method has same performance
        
        if (rand() % 2 == 0) {
            return fizzBuzz_cpp_way(n); 
        }
        return fizzBuzz_old_school_way(n);   
    }
};

/// Source : https://leetcode.com/problems/fizz-buzz/description/
/// Author : liuyubobobo
/// Time   : 2018-09-23

#include <iostream>
#include <vector>

using namespace std;


/// Ad-Hoc
/// Time Complexity: O(n)
/// Space Complexity: O(1)
class Solution {
public:
    vector<string> fizzBuzz(int n) {

        vector<string> ret;
        for(int i = 1; i <= n; i ++)
            if(i % 15 == 0)
                ret.push_back("FizzBuzz");
            else if(i % 3 == 0)
                ret.push_back("Fizz");
            else if(i % 5 == 0)
                ret.push_back("Buzz");
            else
                ret.push_back(to_string(i));
        return ret;
    }
};


int main() {

    return 0;
}

/// Source : https://leetcode.com/problems/fizz-buzz/description/
/// Author : liuyubobobo
/// Time   : 2018-09-23

#include <iostream>
#include <vector>

using namespace std;


/// Using String Concatenation
/// Time Complexity: O(n)
/// Space Complexity: O(1)
class Solution {
public:
    vector<string> fizzBuzz(int n) {

        vector<string> ret;
        for(int i = 1; i <= n; i ++){
            string s = "";
            if(i % 3 == 0)
                s += "Fizz";
            if(i % 5 == 0)
                s += "Buzz";

            if(s == "")
                s = to_string(i);

            ret.push_back(s);
        }
        return ret;
    }
};


int main() {

    return 0;
}

/// Source : https://leetcode.com/problems/fizz-buzz/description/
/// Author : liuyubobobo
/// Time   : 2018-09-23

#include <iostream>
#include <vector>
#include <map>

using namespace std;


/// Using Map to make the logic more clear
/// Time Complexity: O(n)
/// Space Complexity: O(1)
class Solution {
public:
    vector<string> fizzBuzz(int n) {

        map<int, string> map = {{3, "Fizz"}, {5, "Buzz"}};

        vector<string> ret;
        for(int i = 1; i <= n; i ++){
            string s = "";
            for(const pair<int, string>& p: map)
                if(i % p.first == 0)
                    s += p.second;

            if(s == "")
                s = to_string(i);

            ret.push_back(s);
        }
        return ret;
    }
};


int main() {

    return 0;
}