f(n) = f(n-1) + f(n-2) 实现（递归与非递归运行时间比较）
Fibonacci 算法递归实现与非递归实现时间比较：
public class Question1 {/** * @param args */public static void main(String[] args) {long start,end;int n=50;start = System.currentTimeMillis();getWays(n);end = System.currentTimeMillis();System.out.println("Non recursive cost time :"+ (end-start));start = System.currentTimeMillis();getWays_1(n);end = System.currentTimeMillis();System.out.println("recursive cost time :"+ (end-start));}public static long getWays(int n){// TODO Auto-generated method stublong[] f = new long[n+1];f[1]=1;f[2]=2;for(int i=3;i<=n;i++){f[i]=f[i-1]+f[i-2];}return f[n];}public static long getWays_1(int n){if(n==1){return 1;}if(n==2){return 2;}return getWays_1(n-1)+ getWays_1(n-2);}}