题解 | #斐波那契数列#

斐波那契数列的公式:第一项为0,第二项为1,然后从第三项开始套公式 An = A(n-1) + A(n-2)

public int Fibonacci(int n) {
    if (n <= 0) return 0;
    if(n == 1 || n == 2) return 1;

    int a0 = 0;
    int a1 = 1;
    int an = 0;
    for (int i = 2; i <= n; ++i) {
        an = a0 + a1;
        a0 = a1;
        a1 = an;
    }
    return an;
}