dfs 确定每一个位置上填写的数字#include
#include
#include
#include
#include
using namespace std;int n;
int A[18];
int p[40];
int vis[18];int is_prime(int n){
for(...
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其他好文 时间：
2015-05-28 23:19:52
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344
Description
Two positive integers are said to be relatively prime to each other if the Great Common Divisor (GCD) is 1. For instance, 1, 3, 5, 7, 9…are all relatively prime to 2006.Now your job is eas...
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移动开发 时间：
2015-05-28 21:37:06
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143
Problem Description
Given a number N, you are asked to count the number of integers between A and B inclusive which are relatively prime to N.
Two integers are said to be co-prime or relatively prime...
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其他好文 时间：
2015-05-27 10:25:02
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152
The set of ribs denoted by 7331 is prime; the three ribs 733 are prime; the two ribs 73 are prime, and, of course, the last rib, 7, is prime. The nu.....
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其他好文 时间：
2015-05-25 21:54:52
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96
Description:Count the number of prime numbers less than a non-negative number, n.思路分析：这题是一道数学题，求小于n的所有质数。容易想到的思路是定义个isPrime的判定函数，对小于n的数一个一个判定，但是时间复杂度O（N^2）。有没有更快的算法呢？有，这是一个经典的找质数的算法，Sieve of Eratosthe...
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其他好文 时间：
2015-05-25 16:47:52
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128
题目如下：
A reversible prime in any number system is a prime whose "reverse" in that number system is also a prime. For example in the decimal system 73 is a reversible prime because its reverse 37 is al...
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其他好文 时间：
2015-05-25 14:39:05
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140
Sum of Consecutive Prime Numbers
Description
Some positive integers can be represented by a sum of one or more consecutive prime numbers. How many such representations does a given positive integer have? For example, the integer 53 has two representation...
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其他好文 时间：
2015-05-25 14:37:58
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127
Prime Distance
Time Limit: 1000MS
Memory Limit: 65536K
Total Submissions: 13459
Accepted: 3578
Description
The branch of mathematics called number theory is about prope...
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其他好文 时间：
2015-05-23 11:31:57
阅读次数：
127
http://acm.hdu.edu.cn/showproblem.php?pid=1016这道题是经典的素数环问题,相邻的两个数之和是素数。解题方法：用的是深搜，以1为起点，搜索，下一个数为出去前面的数字的集合。（用vis数组记录访问过的节点）剪枝:当前搜索值与数组前一个值之和不为素数的时候返回。...
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其他好文 时间：
2015-05-23 06:23:53
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155
Description
On an alien planet, every extraterrestrial is born with a number. If the sum of two numbers is a prime number, then two extraterrestrials can be friends. But every extraterrestrial ca...
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其他好文 时间：
2015-05-22 09:43:20
阅读次数：
161
