问题遇到的现象和发生背景
一道PTA比赛题目。
在给定的区间 [m,n] 内,是否存在素数 p、q、r(p<q<r),使得 pq+r、qr+p、rp+q 均是素数?
输入格式:输入给出区间的两个端点 0<m<n≤1000,其间以空格分隔。
输出格式:在一行中输出满足条件的素数三元组的个数。
问题相关代码,请勿粘贴截图
int[] prime = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997};
HashSet<Integer> set = new HashSet<>(1000);
for (int i : prime) {
set.add(i);
}
Scanner sc = new Scanner(System.in);
int m = sc.nextInt(), n = sc.nextInt();
int sum = 0;
for (int x = m; x <= n; x++) {
if (set.contains(x)){
for (int y = x + 1; y <= n; y++) {
if ( set.contains(y)){
for (int z = y + 1; z <= n; z++) {
if (set.contains(z) && set.contains(x * y + z) && set.contains(x * z + y) && set.contains(z * y + x)) {
sum++;
}
}
}
}
}
}
System.out.println(sum);
运行结果及报错内容
5个测试用例,只能过2个。。请帮我看看问题在哪