【剑指offer】面试题10

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

        // 动态规划
        int a = 1, b = 1;
        int tmp;
        for (int i = 3; i <= n; i++) {
            tmp = a + b;
            a = b;
            b = tmp;
        }
        return b;
    }
}