codeforces 274A k-Multiple Free Set

K-Multiple Free Set

Description

A k-multiple free set is a set of integers where there is no pair of integers where one is equal to another integer
multiplied by k. That is, there are no two integers x and y(x < y) from the set, such that y = x·k.

You're given a set of n distinct positive integers. Your task is to find the size of it's largest k-multiple free subset.

Input
The first line of the input contains two integers n and k (1 ≤ n ≤ 105, 1 ≤ k ≤ 109). The next line contains a list of
n distinct positive integers a1, a2, ..., an(1 ≤ ai ≤ 109).

All the numbers in the lines are separated by single spaces.
Output

On the only line of the output print the size of the largest k-multiple free subset of {a1, a2, ..., an}

Sample Input
Input

6 2
2 3 6 5 4 10

Output

3

Hint
In the sample input one of the possible maximum 2-multiple free subsets is {4, 5, 6}

代码：

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
long long a[100010];
int s[100010];
int main()
{
int n,k,i;
while(~scanf("%d%d",&n,&k))
{
for(i=0;i<n;i++)
scanf("%lld",&a[i]);
sort(a,a+n);
memset(s,0,sizeof(s));
int ans=n;
for(i=0;i<n;i++)
{
if(s[i])
continue;
int l=i+1,r=n;
long long tmp=k*a[i];
while(r>=l)
{
int mid=(l+r)/2;
if(a[mid]==tmp)
{
s[mid]=true;
ans--;
break;
}
else if(a[mid]>tmp)
r=mid-1;
else
l=mid+1;
}
}
printf("%d\n",ans);
}
return 0;
}