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time limit per test : 2 seconds
memory limit per test : 256 megabytes
input : standard input
output : standard output
We know that prime numbers are positive integers that have exactly two distinct positive divisors. Similarly, we’ll call a positive integer t Т-prime, if t has exactly three distinct positive divisors.
You are given an array of n positive integers. For each of them determine whether it is Т-prime or not.
The first line contains a single positive integer, n (1 ≤ n ≤ 105), showing how many numbers are in the array. The next line contains n space-separated integers xi (1 ≤ xi ≤ 1012).
Please, do not use the %lld specifier to read or write 64-bit integers in С++. It is advised to use the cin, cout streams or the %I64d specifier.
Print n lines: the i-th line should contain “YES” (without the quotes), if number xi is Т-prime, and “NO” (without the quotes), if it isn’t.
3
4 5 6
YES
NO
NO
其实就是个判断素数的水题,时间为两秒,但用了常规的方法(直接用for遍历)之后发现一直tle,可能有个样例是数量很多并且数字都很大,于是就对数字先进行预处理,把非素数给标记,然后对于每一次的输入用O(1)的时间来判断是否为素数。
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