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author | mjfernez <mjfernez@gmail.com> | 2020-02-03 23:04:10 -0500 |
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committer | mjfernez <mjfernez@gmail.com> | 2020-02-03 23:04:10 -0500 |
commit | 8e431d287c0e89041506da4c4da57e3e3d657d72 (patch) | |
tree | b6cd296fbdd75d1421fe84a82cf3eec859407dcb /10001prime.c | |
parent | e6a7399134b3dc08f9e6e9c9c74e39ac449b8538 (diff) | |
download | Project_Euler_Solutions-8e431d287c0e89041506da4c4da57e3e3d657d72.tar.gz |
cleanup, added c translations for some
Diffstat (limited to '10001prime.c')
-rw-r--r-- | 10001prime.c | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/10001prime.c b/10001prime.c new file mode 100644 index 0000000..2ef3bd8 --- /dev/null +++ b/10001prime.c @@ -0,0 +1,42 @@ +#include <stdio.h> +#include <stdlib.h> +#include <math.h> +int n = 1000000; + +int *listPrimes(int num){ + int i; + int *primes; + int *sieve = (int *) malloc(num * sizeof(int)); + //initialize to all 1s (except 0 and 1 which are not prime) + for(i = 2; i < num; i++) + sieve[i] = 1; + for(i = 2; i < ceil(sqrt(num)); i++){ + if(sieve[i] == 1){ + int j = i * i; + while(j < num){ + sieve[j] = 0; + j += i; + } + } + } + + //now check which were prime + int s = 0; + primes = (int *) malloc(sizeof(int)); + for(i = 2; i < num; i++){ + if(sieve[i]){ + primes[s] = i; + s++; + primes = (int *) realloc (primes, (s + 1) * sizeof(int)); + } + } + + return primes; +} + +int main(){ + int *p = listPrimes(n); + int prime10001 = p[10000]; + printf("%d\n", prime10001); + return 0; +} |