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1 | // finds lowest index where predicate turns true. |
2 | // returns "to" when predicate is false on whole range. |
3 | // Predicate operates on a range and returns true |
4 | // iff any value in the range is contained in the set. |
5 | static <A> int indexOfRangePredicate(int from default 0, int to, IF2<Int, Int, Bool> pred) { |
6 | // interval empty? |
7 | if (from >= to) ret to; |
8 | |
9 | // predicate false on whole range? |
10 | if (!pred.get(from, to)) ret to; |
11 | |
12 | while ping (to-from > 1) { |
13 | // predicate turns true somewhere in range. split in middle. |
14 | int mid = (from + to) >>> 1; |
15 | |
16 | // check lower half |
17 | if (pred.get(from, mid)) |
18 | // predicate turns true in lower half. move there. |
19 | to = mid; |
20 | else |
21 | // lower half is clean, move to higher half |
22 | from = mid; |
23 | } |
24 | |
25 | // we've narrowed things down to at most one element, return index |
26 | ret from; |
27 | } |
Began life as a copy of #1029232
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Snippet ID: | #1030504 |
Snippet name: | indexOfRangePredicate |
Eternal ID of this version: | #1030504/15 |
Text MD5: | d3d710b3f64f084feca11160b670f7d3 |
Transpilation MD5: | c0696142e28a9d9e56f066aba623fbfa |
Author: | stefan |
Category: | javax |
Type: | JavaX fragment (include) |
Public (visible to everyone): | Yes |
Archived (hidden from active list): | No |
Created/modified: | 2021-01-03 22:34:40 |
Source code size: | 877 bytes / 27 lines |
Pitched / IR pitched: | No / No |
Views / Downloads: | 222 / 315 |
Version history: | 14 change(s) |
Referenced in: | [show references] |