Hdu 20,441 Little Bees ... (recursive)

A little bee ...

http://acm.hdu.edu.cn/showproblem.php?pid=2044

Time limit:2000/1000 MS (java/others)

Memory limit:65536/32768 K (java/others)

Problem Description

A trained bee can only crawl to the adjacent hive on the right and not crawl in reverse. Please program the number of possible routes by which bees climb from hive A to hive B. The structure of the hive is shown below.

Input

The first line of input data is an integer n that represents the number of test instances, then n rows of data, each containing two integers a and B (0<a<b<50).

This article URL address: http://www.bianceng.cn/Programming/sjjg/201410/45515.htm

Output

For each test instance, export the number of possible routes where the bee crawled from hive A to hive B, and the output of each instance occupies one row.

Sample Input

21 23 6

Sample Output

13

It's clear that lattice n can come from n-1 and n-2, so it's the Fibonacci relationship.

Notice that the a=1,b=49 is a super int, and you want to use long long.

Complete code:

/*0ms,208kb*/
    
#include <cstdio>  
    
long long f[50];  
    
int main ()  
{  
    int T, a, B, I;  
    F[1] = f[2] = 1;  
    for (i = 3; i < ++i) f[i] = F[i-1] + f[i-2];  
    scanf ("%d", &t);  
    while (t--)  
    {  
        scanf ("%d%d", &a, &b);  
        printf ("%i64d\n", F[b-a + 1]);  
    return 0;  
}