Not able to find an efficient way

#1

Can you tell an efficient way to solve this problem, using my approach I am not able to pass for all test cases.

#2

Hey
this question requires the use of the concept Sieve of Eratosthenes that is covered under the topic Number Theory . Try that.

#3

#include #include #include using namespace std; #define N 55000001 int main() { int n; scanf("%d",&n); vector prime; vector arr(N,false); //memset(arr,false,arr.size()); arr[2]=true; for(int i=3;i<N;i+=2){ arr[i]=true; } for(int i=3;ii<N;i+=2){ if(arr[i]){ for(int j=ii;j<N;j+=i){ arr[j]=false; } } } for(int i=0;i<N;i++){ if(arr[i]) prime.push_back(i); } // for(int i=1;i<n;i++){ // printf("%d “,prime[i]); // } if(n>=prime.size()) printf(“Hi”); else printf(”%d",prime[n-1]); return 0; }

#4

I have used sieve of eratosthenenes but still one test case is failing, because constrains are very large

#5

Hey @pulkit_99
use long long int instead of int, that’ll help for sure.