斐波拉契数列 优化

#include <iostream>using namespace std;long a[1000];//斐波拉契数列long fib(int n){    if(n<=1)        return n;    if(a[n]!=0)return a[n];//将已经计算过得值存放起来    return a[n] = fib(n-1)+fib(n-2);}int main(){    cout << fib(50) << endl;    return 0;}