Computer Transformation

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 4842    Accepted Submission(s): 1769

Problem Description

A sequence consisting of one digit, the number 1 is initially written into a computer. At each successive time step, the computer simultaneously tranforms each digit 0 into the sequence 1 0 and each digit 1 into the sequence 0 1. So, after the first time step, the sequence 0 1 is obtained; after the second, the sequence 1 0 0 1, after the third, the sequence 0 1 1 0 1 0 0 1 and so on.

How many pairs of consequitive zeroes will appear in the sequence after n steps?

 

Input

Every input line contains one natural number n (0 < n ≤1000).

 

Output

For each input n print the number of consecutive zeroes pairs that will appear in the sequence after n steps.

 

Sample Input

2

3

 

Sample Output

1

1

做这道题，纯粹是一道大数的题，当然你需要推导出这个公式f[n]=f[n-1]+2*f[n-2];

1 #include
           
             2 const int maxn=1000; 3 int arr[maxn+1][305]={
         0}; 4 int len=1; 5 void LargeNum() 6 { 7      arr[1][0]=1; 8     for(int i=2;i<=maxn;i++) 9     {10         int c=0;11         for(int j=0;j
            
             9)15               len++;16            c=arr[i][j]/10;17              arr[i][j]%=10;18         }19     }20 21 }22 int main( void )23 { 24     int n,i;25     LargeNum();26     while(scanf("%d",&n)==1)27     {28         if(n==1)puts("0");29         else30         {31         for(i=len;arr[n-1][i]==0;i--);32         for(int j=i;j>=0;j--)33               printf("%d",arr[n-1][j]);34         puts("");35         }36     }37     return 0;38 }