Goで某言語のように存在しなかったら-1を返す版のバイナリサーチ

binary_search.go

func BinarySearch(data []int, find int, from int, to int) int {
  center := (from + to) / 2

  if from > to {
    return -1
  }

  if find == data[center] {
    return center
  } else if find < data[center] {
    return BinarySearch(data, find, from, center-1)
  } else {
    return BinarySearch(data, find, center+1, to)
  }

}