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| 1 | +object Utils { |
| 2 | + |
| 3 | + val in = { |
| 4 | + val lines = scala.io.Source.stdin.getLines |
| 5 | + lines flatMap (_ split ' ' filter (_.nonEmpty)) |
| 6 | + } |
| 7 | + |
| 8 | + def nextInt = in.next.toInt |
| 9 | + |
| 10 | + val fibs: Stream[Long] = 1L #:: fibs.scanLeft(2L)(_ + _) |
| 11 | + |
| 12 | + val primes: Stream[Int] = 2 #:: (Stream.from(3, 2) filter (n => primes.view takeWhile (p => p*p <= n) forall (n % _ != 0))) |
| 13 | + |
| 14 | + @annotation.tailrec |
| 15 | + def gcd(a: Int, b: Int): Int = if (b == 0) a else gcd(b, a % b) |
| 16 | + |
| 17 | + def lcm(a: Int, b: Int): Int = a / gcd(a, b) * b |
| 18 | + |
| 19 | + @annotation.tailrec |
| 20 | + def binarySearch[T, U](key: U, xs: IndexedSeq[T], from: Int, end: Int, keyExtract: (T) => U = (x:T) => x)(implicit ordering: Ordering[U]): Option[Int] = { |
| 21 | + if (from >= end) None |
| 22 | + else { |
| 23 | + val mid = (from + end) / 2 |
| 24 | + val t = keyExtract(xs(mid)) |
| 25 | + val cmp = ordering.compare(key, t) |
| 26 | + if (cmp < 0) binarySearch(key, xs, from, mid, keyExtract) |
| 27 | + else if (cmp > 0) binarySearch(key, xs, mid + 1, end, keyExtract) |
| 28 | + else Some(mid) |
| 29 | + } |
| 30 | + } |
| 31 | + |
| 32 | + def lowerBound[T, U](key: U, iseq: IndexedSeq[T], from: Int, end: Int, keyExtract: (T) => U = (x:T) => x)(implicit ordering: Ordering[U]): Int = { |
| 33 | + var lo = from |
| 34 | + var hi = end - 1 |
| 35 | + while (lo <= hi) { |
| 36 | + val mid = (lo + hi) / 2 |
| 37 | + if (ordering.lteq(key, keyExtract(iseq(mid)))) |
| 38 | + hi = mid - 1 |
| 39 | + else |
| 40 | + lo = mid + 1 |
| 41 | + } |
| 42 | + hi + 1 |
| 43 | + } |
| 44 | + |
| 45 | + def upperBound[T, U](key: U, iseq: IndexedSeq[T], from: Int, end: Int, keyExtract: (T) => U = (x:T) => x)(implicit ordering: Ordering[U]): Int = { |
| 46 | + var lo = from |
| 47 | + var hi = end - 1 |
| 48 | + while (lo <= hi) { |
| 49 | + val mid = (lo + hi) / 2 |
| 50 | + if (ordering.lt(key, keyExtract(iseq(mid)))) |
| 51 | + hi = mid - 1 |
| 52 | + else |
| 53 | + lo = mid + 1 |
| 54 | + } |
| 55 | + hi + 1 |
| 56 | + } |
| 57 | + |
| 58 | +} |
| 59 | + |
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