Hat's Fibonacci

Problem Description

A Fibonacci sequence is calculated by adding the previous two members the sequence, with the first two members being both 1.
F(1) = 1, F(2) = 1, F(3) = 1,F(4) = 1, F(n>4) = F(n - 1) + F(n-2) + F(n-3) + F(n-4)
Your task is to take a number as input, and print that Fibonacci number.

 

Input

Each line will contain an integers. Process to end of file.

 

Output

For each case, output the result in a line.

 

Sample Input

100

题解：大数之和。滚动数组求解。

#include <iostream>
#include <cstdio>
#include <cstring>

using namespace std;

int t[6][2555];

int main()
{
	int n;
	while(scanf("%d",&n) != EOF)
	{
		memset(t,0,sizeof(t));
		t[0][0] = 1;
		t[1][0] = 1;
		t[2][0] = 1;
		t[3][0] = 1;
		for(int i = 4;i < n;i++)
		{
			int carry = 0;
			int k = i % 4;
			for(int j = 0;j < 2500;j++)
			{
				int x = t[0][j] + t[1][j] + t[2][j] + t[3][j];
				t[k][j] = x + carry;
				carry = t[k][j] / 10;
				t[k][j] %= 10;
			}
		}
		int k = 2500;
		while(t[(n - 1) % 4][--k] == 0);
		for(int i = k;i >= 0;i--)
		{
			printf("%d",t[(n - 1) % 4][i]);
		}
		
		printf("\n");
		
	}
	
	
	return 0;
}