lightoj-1006-Hex-a-bonacci【思维】

最新推荐文章于 2018-09-04 18:36:54 发布

Somethingwll

最新推荐文章于 2018-09-04 18:36:54 发布

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本文介绍了一个关于Hex-a-bonacci数列的问题，通过分析递归算法的缺陷，提出了使用动态规划的方法来解决大规模数据输入时可能出现的整数溢出问题。文章详细展示了优化后的代码实现过程，并给出了具体的样例输入输出。

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题目链接：点击打开链接

1006 - Hex-a-bonacci

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Time Limit: 0.5 second(s)

Memory Limit: 32 MB

Given a code (not optimized), and necessary inputs, you have to find the output of the code for the inputs. The code is as follows:

int a, b, c, d, e, f;
int fn( int n ) {
    if( n == 0 ) return a;
    if( n == 1 ) return b;
    if( n == 2 ) return c;
    if( n == 3 ) return d;
    if( n == 4 ) return e;
    if( n == 5 ) return f;
    return( fn(n-1) + fn(n-2) + fn(n-3) + fn(n-4) + fn(n-5) + fn(n-6) );
}
int main() {
    int n, caseno = 0, cases;
    scanf("%d", &cases);
    while( cases-- ) {
        scanf("%d %d %d %d %d %d %d", &a, &b, &c, &d, &e, &f, &n);
        printf("Case %d: %d\n", ++caseno, fn(n) % 10000007);
    }
    return 0;
}

Input

Input starts with an integer T (≤ 100), denoting the number of test cases.

Each case contains seven integers, a, b, c, d, e, f and n. All integers will be non-negative and 0 ≤ n ≤ 10000 and the each of the others will be fit into a 32-bit integer.

Output

For each case, print the output of the given code. The given code may have integer overflow problem in the compiler, so be careful.

Sample Input

Output for Sample Input

0 1 2 3 4 5 20

3 2 1 5 0 1 9

4 12 9 4 5 6 15

9 8 7 6 5 4 3

3 4 3 2 54 5 4

Case 1: 216339

Case 2: 79

Case 3: 16636

Case 4: 6

Case 5: 54

题解：用递归会TLE，而且数据会爆 int

#include<cstdio>
#include<algorithm>
#include<cstring>
#define LL long long
using namespace std;
const LL Q=10000007;
LL a,b,c,d,e,f,n;
LL s[1000010];
int get()
{
	s[0]=a; s[1]=b; s[2]=c;
	s[3]=d; s[4]=e; s[5]=f;
	for(int i=6;i<=n;i++)
		s[i]=(s[i-1]+s[i-2]+s[i-3]+s[i-4]+s[i-5]+s[i-6])%Q;
	return s[n];
}
int main()
{
	int t,text=0;
	scanf("%d",&t);
	while(t--)
	{
		scanf("%lld %lld %lld %lld %lld %lld %lld",&a,&b,&c,&d,&e,&f,&n);
		printf("Case %d: %lld\n",++text,get()%Q); // 因为 a，b，c，d，e，f可能会大于 Q 
	}
	return 0;
}