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  1. #include <stdio.h>
  2. #include <math.h>
  3.  
  4. #define N_PRIME 700000
  5.  
  6. int prime_table[N_PRIME];
  7.  
  8. int main () {
  9. int p, i, n;
  10. prime_table[0] = 2;
  11. prime_table[1] = 3;
  12.  
  13. p = 5;
  14. n = 2;
  15. for (i = 2; i < N_PRIME; p += n, n = 6 - n) {
  16. int j, limit = sqrt(p);
  17. for (j = 2; j < i && prime_table[j] <= limit; ++j)
  18. if (p % prime_table[j] == 0)
  19. break;
  20. if (j >= i || prime_table[j] > limit)
  21. prime_table[i++] = p;
  22. }
  23. printf("%d\n", prime_table[N_PRIME - 1]);
  24. return 0;
  25. }
  26.  
Time limit exceeded #stdin #stdout 5s 4560KB
stdin
Standard input is empty
stdout
Standard output is empty