习题10-6 连续素数之和 UVa1210

标签：计数问题   数论   

1.解题思路：点击打开链接

2.解题思路：本题要求寻找连续个素数相加为n的个数。由于n的范围不大， 因此可以事先打表。计算好所有的连续和的个数，最后直接输出即可。

3.代码：

#define _CRT_SECURE_NO_WARNINGS 
#include<iostream>
#include<algorithm>
#include<string>
#include<sstream>
#include<set>
#include<vector>
#include<stack>
#include<map>
#include<queue>
#include<deque>
#include<cstdlib>
#include<cstdio>
#include<cstring>
#include<cmath>
#include<ctime>
#include<functional>
using namespace std;

#define N 10000+5
int vis[N];
int d[N];
vector<int>primes;

void init()
{
	int m = sqrt(N);
	memset(vis, 0, sizeof(vis));
	memset(d, 0, sizeof(d));
	for (int i = 2; i < m; i++)if (!vis[i])
	for (int j = i*i; j < N; j += i)
		vis[j] = 1;
	for (int i = 2; i < N;i++)
	if (!vis[i])
		primes.push_back(i);
	int len = primes.size();
	for (int i = 0; i < len; i++)
	{
		int sum = primes[i];
		int j = i + 1;
		while (j < len&&sum < N)
		{
			d[sum]++;
			sum += primes[j]; j++;
		}
	}
}

int main()
{
	//freopen("t.txt", "r", stdin);
	init();
	int n;
	while (~scanf("%d", &n) && n)
		cout << d[n] << endl;
	return 0;
}

习题10-6 连续素数之和 UVa1210

标签：计数问题   数论   

原文地址：http://blog.csdn.net/u014800748/article/details/45169241