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Remove extra test for Project Euler 044 #1864

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Remove extra test for Project Euler 044 #1864

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85780e0
test: remove unnecessary and slow second check
crhallberg Dec 4, 2025
334cab4
feat(euler44): look ahead checking saves iterations
crhallberg Dec 16, 2025
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feat(euler44): look ahead checking saves iterations
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@crhallberg
crhallberg committed Dec 16, 2025
commit 334cab4554be2acc1dda413545b46c7dad1e40db
14 changes: 11 additions & 3 deletions Project-Euler/Problem044.js
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Expand Up @@ -22,9 +22,17 @@ function problem44(k) {

for (let j = k - 1; j > 0; j--) {
const m = (j * (3 * j - 1)) / 2 // calculate all Pj < Pk
if (isPentagonal(n - m) && isPentagonal(n + m)) {
// Check sum and difference
return n - m // return D
// Check forward, checking n - m doubles work from previous iterations
const sum = n + m
if (isPentagonal(sum)) {
// Check sum - m = n
if (isPentagonal(sum + m)) {
return n // return D
}
// Check sum - n = m
if (isPentagonal(sum + n)) {
return m // return D
}
}
}
}
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