2070 Fibbonacci Number

http://acm.hdu.edu.cn/showproblem.php?pid=2070

Fibbonacci Number

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 13386    Accepted Submission(s): 6675

Problem Description

Your objective for this question is to develop a program which will generate a fibbonacci number. The fibbonacci function is defined as such:

f(0) = 0
f(1) = 1
f(n) = f(n-1) + f(n-2)

Your program should be able to handle values of n in the range 0 to 50.

 

 

Input

Each test case consists of one integer n in a single line where 0≤n≤50. The input is terminated by -1.

 

 

Output

Print out the answer in a single line for each test case.

 

 

Sample Input

  
  

   
   3
4
5
-1
  
  

 

 

Sample Output

  
  

   
   2
3
5


   
   

    
    

     
     Hint
    
    
Note:
   
   
   
    
you can use 64bit integer: __int64
  
  

 

 

用递归和普通方法会超时，需要先打表

#include<stdio.h>
__int64 a[51];
int main()
{   
    int i;
    for(i=2,a[0]=0,a[1]=1;i<=51;i++)
    a[i]=a[i-1]+a[i-2];
    
    int n;
    while(scanf("%d",&n)&&n!=-1)
    {
           printf("%I64d\n",a[n]);
    }
    return 0;
}