哈希表也称为散列表，它是通过关键码值而进行直接访问的数据结构。即它通过把一个关键码映射到表中的一个位置来访问记录，以加快查找速度。当然了在做关键码映射的时候，难免会把不同的关键码映射到相同的位置，这时冲突就产生了。使用平方探测法(Quadratic Probing)可以解决哈希中的冲突问题它的基本思想是：设hash函数为h(key) = d，并且假定其存储结构为循环数组，则当冲突发生时，它接下来需要探测的位置为h+1, h+4, h+9, ……, h+i^2,……直到冲突得到解决。

使用平方探测法进行插入时，i的最大值为size(table)-1;使用平方探测法进行查找时，i的最大值为size(table)。

例如, 现有关键码集为 {47，7，29，11，16，92，22，8，3}，

设：哈希表表长为m=11；哈希函数为Hash(key)=key mod 11；采用平方探测法处理冲突。建哈希表如下：

1145 Hashing - Average Search Time (25 分)

The task of this problem is simple: insert a sequence of distinct positive integers into a hash table first. Then try to find another sequence of integer keys from the table and output the average search time (the number of comparisons made to find whether or not the key is in the table). The hash function is defined to be H(key)=key%TSize where TSizeis the maximum size of the hash table. Quadratic probing (with positive increments only) is used to solve the collisions.

Note that the table size is better to be prime. If the maximum size given by the user is not prime, you must re-define the table size to be the smallest prime number which is larger than the size given by the user.

Each input file contains one test case. For each case, the first line contains 3 positive numbers: MSize, N, and M, which are the user-defined table size, the number of input numbers, and the number of keys to be found, respectively. All the three numbers are no more than 10​4​​. Then N distinct positive integers are given in the next line, followed by M positive integer keys in the next line. All the numbers in a line are separated by a space and are no more than 10​5​​.

For each test case, in case it is impossible to insert some number, print in a line X cannot be inserted. where X is the input number. Finally print in a line the average search time for all the M keys, accurate up to 1 decimal place.