what are the approaches to solve prime1 question

PRIME1

For solving this kind of question Sieve algorithms is one of the best way to solve

you can check my complete solution

first store all the prime numbers from 1 to 10^6 using sieve

And you have give that (n-m<=100000)

Then iterate all the numbers form n to m and use stored prime numbers for check the num is prime or not.

Example take n = 1234567 , m = 1235678

for num = 1234567 , check its a prime num or not for this iterate all the prime numbers upto < sqrt( 1234567) if any prime num divides 1234567 then its not prime , else prime num.

this is the link https://www.codechef.com/viewsolution/11824047 of solution

why have the guys upvoted this question? for upvotes?

yes u must be knowing better.

a common method for this one, just go through this one.

```
https://www.youtube.com/watch?v=eKp56OLhoQs
```

for better undersatnding.