32 lines
749 B
PHP
32 lines
749 B
PHP
<?php
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function Pn($n)
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{
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return $n * (3 * $n - 1) / 2;
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}
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$pn = [];
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for ($i = 1; $i < 2500; $i++) {
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$pn[] = (int) Pn($i);
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}
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$smallest_diff = PHP_INT_MAX;
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echo "Precalculate done\n";
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for ($ij = 0; $ij < sizeof($pn); $ij++) {
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echo "$ij%\n";
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$j = $pn[$ij];
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for ($ik = $ij + 1; $ik < sizeof($pn); $ik++) {
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$k = $pn[$ik];
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$sum = $j + $k;
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if (in_array($sum, $pn)) {
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$diff = (int) abs($k - $j);
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if (in_array($diff, $pn, true)) {
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if ($diff < $smallest_diff) {
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$smallest_diff = $diff;
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echo "Found: Pn($ij)=$j Pn($ik)=$k Sum: $sum Diff: $diff\n";
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}
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}
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}
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}
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}
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echo "Smallest diff: $smallest_diff"; |