杭电_ACM_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

 

Sample Output

4203968145672990846840663646


Note:
No generated Fibonacci number in excess of 2005 digits will be in the test data, ie. F(20) = 66526 has 5 digits.

#include <stdio.h>
#include <string.h>
int f[10000][505] = {0};
int main()
{
    int n, carry, sum, i, j, length;
    //f[number][0] is the length of the number
    f[1][0] = 1;
    f[1][1] = 1;
    f[2][0] = 1;
    f[2][1] = 1;
    f[3][0] = 1;
    f[3][1] = 1;
    f[4][0] = 1;
    f[4][1] = 1;
    while (scanf("%d", &n) != EOF)
    {
        if (n < 5)
        {
            puts("1");
            continue;
        }
        for (i = 5; i <= n; i++)
        {
            f[i][0] = f[i - 1][0];
            carry = 0;
            //splite the number by four
            for (j = 1; j <= f[i][0]; j++)
            {
                sum = f[i -1][j] + f[i - 2][j] + f[i - 3][j] + f[i - 4][j] + carry;
                f[i][j] = sum % 10000;
                carry = sum / 10000;
            }
            //if the carry is not zero, then the length must plus one
            if (carry != 0)
            {
                f[i][0]++;
                f[i][j] = carry;
            }
        }
        //formatted printing
        length = f[n][0];
        printf("%d", f[n][length]);
        for (i = length - 1; i >= 1; i--)
            printf("%04d",f[n][i]);
        printf("\n");
    }
    return 0;
}

Main points

firstly, you can't use string in C and if the array is big, you must declare in global variable.

secondly, the question is splitting the number by four, or you will accure Runtime Error (ACCESS_VIOLATION). The one diffence with spliting by one is you should use %d firstly, then use %04d.