HDU 5914 Triangle【找规律】【2016中国大学生程序设计竞赛（长春）】

Triangle

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others)
Total Submission(s): 578    Accepted Submission(s): 382

Problem Description

Mr. Frog has n sticks, whose lengths are 1,2, 3⋯n respectively. Wallice is a bad man, so he does not want Mr. Frog to form a triangle with three of the sticks here. He decides to steal some sticks! Output the minimal number of sticks he should steal so that Mr. Frog cannot form a triangle with
any three of the remaining sticks.

 

Input

The first line contains only one integer T (T≤20), which indicates the number of test cases. 

For each test case, there is only one line describing the given integer n (1≤n≤20).

 

Output

For each test case, output one line “Case #x: y”, where x is the case number (starting from 1), y is the minimal number of sticks Wallice should steal.

 

Sample Input

3456

 

Sample Output

Case #1: 1Case #2: 1Case #3: 2

 

Source

2016中国大学生程序设计竞赛（长春）-重现赛

原题链接：http://acm.hdu.edu.cn/showproblem.php?pid=5914

题意：有n根长度为1-n的木棍，问你最少拿去多少根，使得剩下的不能构成三角形。

经过推测，使得剩下的木棍长度构成Fibobacci数列，就不能构成三角形。

有人直接写答案，但是20个数有点烦，能用循环解决的就不用‘暴力’。

AC代码：

#include <iostream>#include <cstring>#include <cstdio>using namespace std;const int maxn=25;bool vis[maxn];int ans[maxn];int main(){    int x=0,y=1;    vis[1]=true;    while(true)    {        vis[x]=true;        y+=x;        x=y-x;        if(y>maxn)            break;    }    int cnt=0;    for(int i=0; i<maxn; i++)    {        if(!vis[i])            cnt++;        ans[i]=cnt;    }    int T,kase=0;    cin>>T;    int n;    while(T--)    {        cin>>n;        printf("Case #%d: %d\n",++kase,ans[n]);    }    return 0;}

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