Increasing gaps between consecutive Niven numbers: Difference between revisions
Increasing gaps between consecutive Niven numbers (view source)
Revision as of 07:27, 12 May 2020
, 4 years agoMinor performance improvement
(Added C solution) |
m (Minor performance improvement) |
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Line 116:
// Returns the sum of the digits of n given the
// sum of the digits of n - 1
uint64_t digit_sum(uint64_t n, int sum) {
++sum;
while (n > 0 && n % 10 == 0) {
sum -= 9;
n /= 10;
Line 127 ⟶ 125:
}
inline bool divisible(uint64_t n, uint64_t d) {
int main()▼
if ((d & 1) == 0 && (n & 1) == 1)
return n % d == 0;
}
▲int main() {
// Print numbers with commas
std::cout.imbue(std::locale(""));
Line 136 ⟶ 139:
std::cout << "Gap index Gap Niven index Niven number\n";
for (uint64_t niven = 1; gap_index <= 32; ++niven) {
sum = digit_sum(niven, sum);
if (divisible(niven
if (niven > previous + gap) {
▲ {
gap = niven - previous;
std::cout << std::setw(9) << gap_index++
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