Hello all, I am trying to find the complexity of the below code
include <bits/stdc++.h>
using namespace std;
int main() { // your code goes here long long int n; cin>>n; vectorfactors[1000001]; for(int i=2;i<=n;i++) { for(int j=1;j*i<=n;j++) { factors[j*i].push_back(i); } }
return 0;
}
What I am mainly doing in the code is trying to store factors of all the numbers from 1 to n (n<=1000000). As you can see , factors is a vector of vectors. factors[i] will store all the factors for number i. The code works as follows 1. Fix a number i in the outer loop 2. For all the multiples of i that lies within n, push i as it's factor-->this is being done in the inner loop. According to my calculation, the complexity should be nlog(n) which should easily pass in a time limit of 1s but when I am running the above code on Codechef compiler with n=1000000, the execution time is coming >2s.
If anyone can kindly help, I will be highly obliged. Thank you..