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Pascal's triangle: Difference between revisions
→Recursive(slow)
Line 326:
=== Recursive(slow) ===
In the spirit of the Haskell "think in whole lists" solution here is a list-driven, minimalist solution:
<lang groovy>pascal = { n -> (n <= 1) ? [1] :
However, this solution is horribly inefficient (O(''n''
Program for unformatted output:
<lang groovy>(1..20).each { println "${it}: ${pascal(it)}" }</lang>
Output:
<pre>1: [1]
2: [1, 1]
3: [1, 2, 1]
4: [1, 3, 3, 1]
5: [1, 4, 6, 4, 1]
6: [1, 5, 10, 10, 5, 1]
7: [1, 6, 15, 20, 15, 6, 1]
8: [1, 7, 21, 35, 35, 21, 7, 1]
9: [1, 8, 28, 56, 70, 56, 28, 8, 1]
10: [1, 9, 36, 84, 126, 126, 84, 36, 9, 1]
11: [1, 10, 45, 120, 210, 252, 210, 120, 45, 10, 1]
12: [1, 11, 55, 165, 330, 462, 462, 330, 165, 55, 11, 1]
13: [1, 12, 66, 220, 495, 792, 924, 792, 495, 220, 66, 12, 1]
14: [1, 13, 78, 286, 715, 1287, 1716, 1716, 1287, 715, 286, 78, 13, 1]
15: [1, 14, 91, 364, 1001, 2002, 3003, 3432, 3003, 2002, 1001, 364, 91, 14, 1]
16: [1, 15, 105, 455, 1365, 3003, 5005, 6435, 6435, 5005, 3003, 1365, 455, 105, 15, 1]
17: [1, 16, 120, 560, 1820, 4368, 8008, 11440, 12870, 11440, 8008, 4368, 1820, 560, 120, 16, 1]
18: [1, 17, 136, 680, 2380, 6188, 12376, 19448, 24310, 24310, 19448, 12376, 6188, 2380, 680, 136, 17, 1]
19: [1, 18, 153, 816, 3060, 8568, 18564, 31824, 43758, 48620, 43758, 31824, 18564, 8568, 3060, 816, 153, 18, 1]
20: [1, 19, 171, 969, 3876, 11628, 27132, 50388, 75582, 92378, 92378, 75582, 50388, 27132, 11628, 3876, 969, 171, 19, 1]</pre>
=={{header|Haskell}}==
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