hdu 1431 素數迴文

/*<br />本題給的n的資料很大，但是n > N 的時候的數都是不成立<br />數論真的要好好的去學習<br />*/<br />#include <iostream><br />#include <cstdio><br />#include <cstring><br />#include <cmath><br />using namespace std;</p><p>const int N = 10000000;<br />bool hash[N];<br />int path[1000000];<br />int len;<br />inline void Hash()<br />{<br />memset(hash, false, sizeof(hash));<br />for(int i = 2; i < (int)sqrt(1.0 * N); i++)<br />{<br />if(hash[i])<br />continue;<br />for(int j = i * i; j < N; j += i)<br />hash[j] = true;<br />}<br />}</p><p>inline int change(int n)<br />{<br />int temp = 0;<br />int r = n;<br />while(r)<br />{<br />temp = 10 * temp + r % 10;<br />r /= 10;<br />}<br />if(n == temp)<br />return 1;<br />else<br />return 0;<br />}</p><p>inline void huiw()// 判斷是否是迴文<br />{<br />for(int i = 2; i < N; i++)<br />{<br />if(hash[i])<br />continue;<br />if(change(i) == 1)<br />path[len++] = i;<br />}<br />}<br />int main()<br />{<br />int n, m;<br />len = 0;<br />Hash();<br />huiw();<br />while(cin >> n >> m)<br />{<br />for(int i = 0; i < len; i++)<br />{<br />if(path[0] > m)<br />break;<br />if(path[i] < n)<br />continue;<br />else if(path[i] <= m)<br />printf("%d/n", path[i]);<br />else<br />break;<br />}<br />printf("/n");<br />}<br />}<br />