问题 https://www.codechef.com/problems/MATPH 的链接 所以,我在这个问题上停留了几个小时,我不知道我错在哪里。我使用Eratosthenes的Sieve来查找素数,并将所有素数保存在哈希映射中。在线法官在测试用例上给了我错误的答案。 static void dri(int n) { long large=0;int r=0,x,count=0,p,count1=0; x=(int)Math.sqrt(n); //To understand why I calculated x let's take an example //let n=530 sqrt(530) is 23 so for all the numbers greater than 23 when //we square them they will come out to be greater than n //so now I just have to check the numbers till x because numbers //greater than x will defiantly fail.I think you get //what I'm trying to explain while(r<x) { r = map.get(++count); // Prime numbers will be fetched from map and stored in r int exp = (int) (Math.log(n) / Math.log(r)); //To explain this line let n=64 and r=3.Now, exp will be equal to 3 //This result implies that for r=3 the 3^exp is the //maximum(less than n) value which I can calculate by having a prime in a power if (exp != 1) { //This is just to resolve an error dont mind this line if (map.containsValue(exp) == false) { //This line implies that when exp is not prime //So as I need prime number next lines of code will calculate the nearest prime to exp count1 = exp; while (!map.containsValue(--count1)) ; exp = count1; } int temp = (int) Math.pow(r, exp); if (large < temp) large = temp; } } System.out.println(large); }
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慕慕森
TA贡献1856条经验 获得超17个赞
对于每个测试用例,在包含最大漂亮数字的一行中输出≤ N。如果不存在这样的数字,则打印 −1。
我相信4是最小的美丽数,因为2是最小的素数,2^ 2等于4。N 只需要≥ 0。所以, ,并且应该全部打印。我试过了。他们没有。我相信这就是你在CodeChef上失败的原因。dri(0)
dri(1)
dri(2)
dri(3)
−1
我把它留给你自己来了解提到的对你的方法的调用是如何表现的,以及如何处理它。
顺便说一句,将素数保存在地图中有什么意义?列表或排序集不是更合适吗?
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