斐波那契数列java实现

Posted 2021-11-25 dxxdsw

java  实现斐波那契数列
以下是Java代码实现(递归与递推两种方式)：
    import java.util.Scanner;  
    /** 
     * Fibonacci 
     * 
     * @author tongqian.zhang 
     */  
    public class Fibonacci {  
         public static void main(String[] args) {  
            Scanner scanner = new Scanner(System.in);  
            System.out.println("Please input this fibonacci n:");  
            int n = scanner.nextInt(); // 假设输入为大于零的整数  
            System.out.println(fibonacci(6) + ":" + fibonacciNormal(6));  
            int sum = 0;  
            for(int i = 1; i <= n; i++){  
                sum += fibonacci(i);  
            }  
            System.out.println(sum);  
        }  
        // 递归实现方式  
        public static int fibonacci(int n){  
            if(n <= 2){  
                return 1;  
            }else{  
                return fibonacci(n-1) + fibonacci(n-2);  
            }  
        }  
        // 递推实现方式  
        public static int fibonacciNormal(int n){  
            if(n <= 2){  
                return 1;  
            }  
            int n1 = 1, n2 = 1, sn = 0;  
            for(int i = 0; i < n - 2; i ++){  
                sn = n1 + n2;  
                n1 = n2;  
                n2 = sn;  
            }  
            return sn;  
        }  
    }