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 }