412. Fizz Buzz

Description

Write a program that outputs the string representation of numbers from 1 to n.

But for multiples of three it should output “Fizz” instead of the number and for the multiples of five output “Buzz”. For numbers which are multiples of both three and five output “FizzBuzz”.

Example:

n = 15,

Return:
[
"1",
"2",
"Fizz",
"4",
"Buzz",
"Fizz",
"7",
"8",
"Fizz",
"Buzz",
"11",
"Fizz",
"13",
"14",
"FizzBuzz"
]

Solution

Iterative

class Solution {
    public List<String> fizzBuzz(int n) {
        List<String> result = new ArrayList<>();
        
        for (int i = 1; i <= n; ++i) {
            if (i % 3 == 0 && i % 5 == 0) {
                result.add("FizzBuzz");
            } else if (i % 3 == 0) {
                result.add("Fizz");
            } else if (i % 5 == 0) {
                result.add("Buzz");
            } else {
                result.add(Integer.toString(i));
            }
        }
        
        return result;
    }
}

Follow up, not using mod

如果不许使用mod呢？可以使用额外的两个count来计算，每递增到3或5就清零。

public class Solution {
    public List<String> fizzBuzz(int n) {
        List<String> ret = new ArrayList<String>(n);
        for(int i=1,fizz=0,buzz=0;i<=n ;i++){
            fizz++;
            buzz++;
            if(fizz==3 && buzz==5){
                ret.add("FizzBuzz");
                fizz=0;
                buzz=0;
            }else if(fizz==3){
                ret.add("Fizz");
                fizz=0;
            }else if(buzz==5){
                ret.add("Buzz");
                buzz=0;
            }else{
                ret.add(String.valueOf(i));
            }
        } 
        return ret;
    }
}