HDU2018(数学推导)

来源：互联网发布：淘宝最帅男模特编辑：程序博客网时间：2024/06/01 22:44

题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=2018

解题思路：

第n年的母牛数 = 第n-1年的母牛数 + 第n-3年的母牛数（能生产的母牛数）

完整代码：

#include <functional>#include <algorithm>#include <iostream>#include <fstream>#include <sstream>#include <iomanip>#include <numeric>#include <cstring>#include <climits>#include <cassert>#include <complex>#include <cstdio>#include <string>#include <vector>#include <bitset>#include <queue>#include <stack>#include <cmath>#include <ctime>#include <list>#include <set>#include <map>using namespace std;#pragma comment(linker, "/STACK:102400000,102400000")typedef long long LL;typedef double DB;typedef unsigned uint;typedef unsigned long long uLL;/** Constant List .. **/ //{const int MOD = int(1e9)+7;const int INF = 0x3f3f3f3f;const LL INFF = 0x3f3f3f3f3f3f3f3fLL;const DB EPS = 1e-9;const DB OO = 1e20;const DB PI = acos(-1.0); //M_PI;int a[56];int main(){    #ifdef DoubleQ    freopen("in.txt","r",stdin);    #endif    int n;    a[0] = 1;    a[1] = 1;    a[2] = 2;    a[3] = 3;    a[4] = 4;    for(int i = 5; i < 56 ; i ++)        a[i] = a[i - 1] + a[i - 3];    while(cin >> n)    {        if(n == 0)            break;        cout << a[n] << endl;    }}

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