NEU OJ 1649 GMZ ' s pretty number

First, a linear prime sieve, 1 to 10000000 of the prime numbers are screened out, and then violently run through all possible values, make a table, query the time O (1) Efficiency out of the solution.

#include <cstdio>#include<cstring>#include<cmath>#include<algorithm>#include<queue>#include<cstring>using namespacestd;Const LongN =10000000;Long LongPrime[n] = {0},num_prime =0;intIsnotprime[n] = {1,1};intr[10000000+Ten];intans[10000000+Ten];intMain () {memset (R),0,sizeof(R)); memset (ans,0,sizeof(ans));  for(Longi =2; i < N; i + +)    {        if(!Isnotprime[i]) prime[num_prime++]=i; //key points 1         for(Longj =0; J < num_prime && I * prime[j] < N; J + +) {Isnotprime[i* Prime[j]] =1; if( ! (i% prime[j]))//Key points 2                 Break; }    }      for(intI=0; i<num_prime;i++)    {         for(intj=i+1; j<num_prime;j++)        {            if(prime[i]*prime[j]>10000000) Break; R[prime[i]*prime[j]]=1; }} ans[0]=0;  for(intI=1; i<=10000000; i++)    {        if(r[i]==1) ans[i]=ans[i-1]+1; Elseans[i]=ans[i-1]; }    intLL,RR;  while(~SCANF ("%d%d",&ll,&RR)) {printf ("%d\n", ans[rr]-ans[ll-1]); }    return 0;} 

NEU OJ 1649 GMZ ' s pretty number