【水题+数学推导】杭电 hdu 2018 母牛的故事

/* THE PROGRAM IS MADE BY PYY *//*----------------------------------------------------------------------------//    Copyright (c) 2012 panyanyany All rights reserved.    URL   : http://acm.hdu.edu.cn/showproblem.php?pid=2018    Name  : 2018 母牛的故事    Date  : Thursday, February 16, 2012    Time Stage : half an hour    Result:53614612012-02-16 16:47:38Accepted20180MS216K982 BC++pyyTest Data :Review ://----------------------------------------------------------------------------*/#include <stdio.h>#define MAXN(56)#define DB/##/int can[MAXN] = {0, 1, 1, 1, 1}, cow[MAXN] ;int main (){int i, j, n ;// 计算第i年有多少头可生育的母牛for (i = 5 ; i <= 55 ; ++i)can[i] = can[i-1] + can[i-3] ;// 根据今年可生育的母牛数，和上一年的总牛数，可以算出今年的总牛数。cow[0] = 0 ;for (i = 1 ; i <= 55 ; ++i)cow[i] = cow[i-1] + can[i] ;while (scanf("%d", &n), n){printf ("%d\n", cow[n]) ;}return 0 ;}