POJ 2191
只会打表
#include <iostream> #include <cstdio> #include <cstdlib> #include <cstring> using namespace std; int main() { int Mec[10] = { 11, 23, 29, 37, 41, 43, 47, 53, 59 }; char st[10][100] = { "23 * 89 = 2047 = ( 2 ^ 11 ) - 1", "47 * 178481 = 8388607 = ( 2 ^ 23 ) - 1", "233 * 1103 * 2089 = 536870911 = ( 2 ^ 29 ) - 1", "223 * 616318177 = 137438953471 = ( 2 ^ 37 ) - 1", "13367 * 164511353 = 2199023255551 = ( 2 ^ 41 ) - 1", "431 * 9719 * 2099863 = 8796093022207 = ( 2 ^ 43 ) - 1", "2351 * 4513 * 13264529 = 140737488355327 = ( 2 ^ 47 ) - 1", "6361 * 69431 * 20394401 = 9007199254740991 = ( 2 ^ 53 ) - 1", "179951 * 3203431780337 = 576460752303423487 = ( 2 ^ 59 ) - 1" }; int n; scanf("%d", &n); for (int i =0; i <9; i++) if (Mec[i] <= n) printf("%s\n", st[i]); return 0; }