ZOJ_1828 Fibonacci Numbers 费波纳奇数列

Fibonacci Numbers

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Time Limit: 1 Second      Memory Limit: 32768 KB

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A Fibonacci sequence is calculated by adding the previous two members of the sequence, with the first two members being both 1.

f(1) = 1, f(2) = 1, f(n > 2) = f(n - 1) + f(n - 2)

Your task is to take a number as input, and print that Fibonacci number.

Sample Input

100

Sample Output

354224848179261915075

Note:

No generated Fibonacci number in excess of 1000 digits will be in the test data, i.e. f(20) = 6765 has 4 digits.

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Source: University of Waterloo Local Contest 1996.10.05

其实这个题目说到底还是大整数的相加问题，类似问题以前也做过，所以不多说什么了，直接贴代码：

 

#include<iostream>
using namespace std;

void Add(int*a, int len1,int* b, int len2)//两个大整数求和，和保存在数组a中
{
    int i,sum;
    int min=len1<=len2?len1:len2;
    for(i=0;i<min;i++)
    {
        sum=a[i]+b[i];
        if(sum>=10)
        {
            a[i]=sum-10;
            a[i+1]++;
        }
        else
        {
            a[i]=sum;
        }
    }
}

void Print(int*c, int len)
{
    int i;
    for(i=len-1;i>=0;i--)
    {
        if(c[i]!=0)break;
    }
    for(;i>=0;i--)
    {
        cout<<c[i];
    }
    cout<<endl;
}


int main(void)
{
    int* a=new int[1000];
    int* b=new int[1000];
    int *temp;
    int i,n;
    while(cin>>n)
    {
        a[0]=1;
        b[0]=1;
        for(i=1;i<1000;i++)a[i]=b[i]=0;
        for(i=3;i<=n;i++)
        {
            Add(a,1000,b,1000);
            temp=a;
            a=b;
            b=temp;
        }
        Print(b,1000);
    }
}