CF 567C(Geometric Progression-map)
#include<cstdio> #include<cstring> #include<cstdlib> #include<algorithm> #include<functional> #include<iostream> #include<cmath> #include<cctype> #include<ctime> #include<map> using namespace std; #define For(i,n) for(int i=1;i<=n;i++) #define Fork(i,k,n) for(int i=k;i<=n;i++) #define Rep(i,n) for(int i=0;i<n;i++) #define ForD(i,n) for(int i=n;i;i--) #define RepD(i,n) for(int i=n;i>=0;i--) #define Forp(x) for(int p=pre[x];p;p=next[p]) #define Forpiter(x) for(int &p=iter[x];p;p=next[p]) #define Lson (x<<1) #define Rson ((x<<1)+1) #define MEM(a) memset(a,0,sizeof(a)); #define MEMI(a) memset(a,127,sizeof(a)); #define MEMi(a) memset(a,128,sizeof(a)); #define INF (2139062143) #define F (100000007) #define MAXN (1000000) typedef long long ll; ll mul(ll a,ll b){return (a*b)%F;} ll add(ll a,ll b){return (a+b)%F;} ll sub(ll a,ll b){return (a-b+(a-b)/F*F+F)%F;} void upd(ll &a,ll b){a=(a%F+b%F)%F;} int n,k; int a[MAXN]; bool b[MAXN]={0}; int l[MAXN]={0}; int cnt[40],cnt2[40]; ll f[MAXN]={0},f2[MAXN]={0}; map<ll,int> S; map<ll,int>::iterator it; int main() { // freopen("C.in","r",stdin); // freopen(".out","w",stdout); scanf("%d%d",&n,&k); For(i,n) { scanf("%d",&a[i]); // while (a[i]%k==0) l[i]++,a[i]/=k; } For(i,n) { if (a[i]%k==0&&S.find(a[i]/k)!=S.end()) f[i]=S[a[i]/k]; it=S.find(a[i]); if (it==S.end()) S[a[i]]=1; else S[a[i]]++; } S.clear(); ForD(i,n) { if (S.find((ll)(a[i])*k)!=S.end()) f2[i]=S[((ll)(a[i])*k)]; it=S.find(a[i]); if (it==S.end()) S[a[i]]=1; else S[a[i]]++; } ll ans=0; For(i,n) ans+=f[i]*f2[i]; cout<<ans<<endl; return 0; }