题目描述
Given a set of distinct integers, print the size of a maximal subset of $S$ where the sum of any $2$ numbers in $\text{S'}$ is not evenly divisible by $k$.
Example
$S=[19,10,12,10,24,25,22]$ $k=4$
One of the arrays that can be created is $S'[0]=[10,12,25]$. Another is $S'[1]=[19,22,24]$. After testing all permutations, the maximum length solution array has $3$ elements.
Function Description
Complete the nonDivisibleSubset function in the editor below.
nonDivisibleSubset has the following parameter(s):
int S[n]: an array of integers
int k: the divisor
Returns
int: the length of the longest subset of $S$ meeting the criteria
Input Format
The first line contains $2$ space-separated integers, $n$ and $k$, the number of values in $S$ and the non factor.
The second line contains $n$ space-separated integers, each an $S[i]$, the unique values of the set.
Constraints
$1 \leq n \leq 10^5$
$1 \le k \le100$
$1\leq S[i]\leq10^{9}$
All of the given numbers are distinct.
Sample Input
STDIN Function
----- --------
4 3 S[] size n = 4, k = 3
1 7 2 4 S = [1, 7, 2, 4]
Sample Output
3
Explanation
The sums of all permutations of two elements from $S=\{1,7,2,4\}$ are:
1 + 7 = 8
1 + 2 = 3
1 + 4 = 5
7 + 2 = 9
7 + 4 = 11
2 + 4 = 6
Only $S'=\{1,7,4\}$ will not ever sum to a multiple of $k=3$.
输入格式
见题面
输出格式
见题面