斐波那契數列 java

題目描述
大家都知道斐波那契數列，現在要求輸入一個整數n，請你輸出斐波那契數列的第n項（從0開始，第0項為0）。其中：n<=39

程式碼1：

public class Solution {
    public int Fibonacci(int n) {
        int a = 0, b = 1;
        int c = 0;
        for(int i = 0; i <= n; i++){
            if(i == 0){
                c = a;
            }else if(i == 1){
                c = b;
            }else if(i > 1){
                c = a + b;
                a = b;
                b = c;
            }
        }
        return c;
    }
}
 

程式碼2：推薦

public class Solution {
    public int Fibonacci(int n) {
        int a = 0, b = 1;
        int c = 0;
        for(int i = 0; i <= n; i++){
            if(i == 1){
                c = b;
            }else if(i > 1){
                c = a + b;
                a = b;
                b = c;
            }
        }
        return c;
    }
}
 

程式碼3：採用遞迴方式

public class Solution {
    public int Fibonacci(int n) {
        int c = 0;
        if(n == 0){
            c = 0;
        }else if(n == 1){
            c = 1;
        }else{
            c = Fibonacci(n - 1) + Fibonacci(n - 2);
        }
        return c;
    }
}