（数学+打表）POJ 2192

原题链接：http://poj.org/problem?id=2191

题意：定义2^p-1（p为素数）的合数为梅森合数。

求求p<=k的梅森合数

分析：实力打一波表

代码：

 1 #include<iostream>  
 2 #include<cstring>  
 3 #include<cstdio>  
 4 using namespace std;  
 5 int main()  
 6 {  
 7     int s[10]={ 11, 23, 29, 37, 41, 43, 47, 53, 59 };  
 8     char st[10][100] ={ "23 * 89 = 2047 = ( 2 ^ 11 ) - 1",  
 9             "47 * 178481 = 8388607 = ( 2 ^ 23 ) - 1",  
10             "233 * 1103 * 2089 = 536870911 = ( 2 ^ 29 ) - 1",  
11             "223 * 616318177 = 137438953471 = ( 2 ^ 37 ) - 1",  
12             "13367 * 164511353 = 2199023255551 = ( 2 ^ 41 ) - 1",  
13             "431 * 9719 * 2099863 = 8796093022207 = ( 2 ^ 43 ) - 1",  
14             "2351 * 4513 * 13264529 = 140737488355327 = ( 2 ^ 47 ) - 1",  
15             "6361 * 69431 * 20394401 = 9007199254740991 = ( 2 ^ 53 ) - 1",  
16             "179951 * 3203431780337 = 576460752303423487 = ( 2 ^ 59 ) - 1" };  
17     int n;  
18     while(scanf("%d",&n)!=EOF)  
19     {  
20         for (int i=0;i<9;i++)  
21             if(s[i]<=n)  
22                 printf("%s
",st[i]);  
23     }  
24     return 0;  
25 }