Catalan numbers/Pascal's triangle: Difference between revisions
→ES6 JavaScript: Functional (distinguishing between first N element of series and Nth distinct Catalan number)
m (→ES6 JavaScript: Deleted one unused generic function) |
(→ES6 JavaScript: Functional (distinguishing between first N element of series and Nth distinct Catalan number)) |
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Line 691:
// CATALAN
//
let
let alternate = xs => xs.reduce(
(a, x, i) => i % 2 === 0 ? a.concat([x]) : a, []
Line 698:
diff = xs => xs.length > 1 ? xs[0] - xs[1] : xs[0];
return
.map((xs, i) => diff(drop(i, xs
}
Line 742:
}
// drop :: Int -> [a] -> [a]
let drop = (n, xs) => xs.slice(n);
Line 749 ⟶ 748:
let tail = xs => xs.length ? xs.slice(1) : undefined;
return
})();</lang>
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