Prime Independence

#include <bits/stdc++.h>

const int N = 100010;

using namespace std;

int n,timnow;
int pre[N],a[N],v[N],cnt[N],Id[500010];
vector<int> g[N],fac[N];

bool find(int x)
{
    for(int i=0;i<(int)g[x].size();i++)
    {
        int p = g[x][i];
        if(v[p] == timnow) continue;
        v[p] = timnow;
        if(!pre[p] || find(pre[p]))
        {
            pre[p] = x;
            return 1;
        }
    }
    return 0;
}

int main()
{
    int T,Te = 0;
    scanf("%d",&T);
    while(T--)
    {
        scanf("%d",&n);
        for(int i=1;i<=n;i++) g[i].clear(),pre[i] = 0,fac[i].clear(),cnt[i]=0;
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&a[i]);
            Id[a[i]] = i;
            int tmp = a[i];
            for(int j=2;j*j<=a[i];j++)
                if(tmp%j==0)
                {
                    fac[i].push_back(j);
                    while(tmp%j==0) tmp/=j, cnt[i]++;
                }
            if(tmp>1) fac[i].push_back(tmp), cnt[i]++;
        } 
        for(int i=1;i<=n;i++)
        {
            for(int j=0;j<(int)fac[i].size();j++)
            {
                int tmp = a[i]/fac[i][j];
                if(Id[tmp])
                {
                    int k = Id[tmp];
                    if(cnt[i]&1) g[i].push_back(k);
                    else g[k].push_back(i);
                }
            }
        }
        int ans = 0;
        for(int i=1;i<=n;i++)
        {
            timnow ++;
            if(find(i)) ans++;
            Id[a[i]] = 0;
        }
        printf("Case %d: %d\n", ++Te, n-ans);
    }
    return 0;
}