To find the nth number of primes

Test instructions

Enter a number n (n <= 200000) and output the bottom n primes.

Ideas:

There are about 210000 primes in 1-3000000. Direct these primes to the table, then the offline query on OK.

Code:

1#include <iostream>2#include <cmath>3#include <cstdio>4#include <cstring>5#include <cstdlib>6#include <algorithm>7#include <queue>8#include <stack>9#include <vector>Ten using namespacestd; OnetypedefLong LongLL; A  - BOOLvisit[3010000+7];  - intprime[3000000+7];  the intans[220000+7]; - voidInit_prim () { -memset (Visit,true,sizeof(visit));  -     intnum =0;  +      for(inti =2; I <=3000000; ++i) {   -         if(Visit[i] = =true){   +num++;  APrime[num] =i;  at         }   -          for(intj =1; ((J <= num) && (i * prime[j] <=3000000)); ++j) {   -Visit[i * Prime[j]] =false;  -             if(i% prime[j] = =0) Break;  -         }   -     }   in } -  to intMain () + { -     //freopen ("Input.txt", "R", stdin); thememset (Prime,0,sizeof(prime)); * Init_prim (); $     intCNT =0;Panax Notoginseng      for(inti =0; I <=3000000; i++){ -         if(Prime[i]) ans[cnt++] =Prime[i]; the     } +     intT; Ascanf"%d", &t); the      while(t--){ +         intN; -scanf"%d", &n); $printf"%d\n", Ans[n-1]); $     } -     return 0; -}

To find the nth number of primes