| 1 | """Bisection algorithms."""
|
|---|
| 2 |
|
|---|
| 3 | def insort_right(a, x, lo=0, hi=None):
|
|---|
| 4 | """Insert item x in list a, and keep it sorted assuming a is sorted.
|
|---|
| 5 |
|
|---|
| 6 | If x is already in a, insert it to the right of the rightmost x.
|
|---|
| 7 |
|
|---|
| 8 | Optional args lo (default 0) and hi (default len(a)) bound the
|
|---|
| 9 | slice of a to be searched.
|
|---|
| 10 | """
|
|---|
| 11 |
|
|---|
| 12 | if hi is None:
|
|---|
| 13 | hi = len(a)
|
|---|
| 14 | while lo < hi:
|
|---|
| 15 | mid = (lo+hi)//2
|
|---|
| 16 | if x < a[mid]: hi = mid
|
|---|
| 17 | else: lo = mid+1
|
|---|
| 18 | a.insert(lo, x)
|
|---|
| 19 |
|
|---|
| 20 | insort = insort_right # backward compatibility
|
|---|
| 21 |
|
|---|
| 22 | def bisect_right(a, x, lo=0, hi=None):
|
|---|
| 23 | """Return the index where to insert item x in list a, assuming a is sorted.
|
|---|
| 24 |
|
|---|
| 25 | The return value i is such that all e in a[:i] have e <= x, and all e in
|
|---|
| 26 | a[i:] have e > x. So if x already appears in the list, i points just
|
|---|
| 27 | beyond the rightmost x already there.
|
|---|
| 28 |
|
|---|
| 29 | Optional args lo (default 0) and hi (default len(a)) bound the
|
|---|
| 30 | slice of a to be searched.
|
|---|
| 31 | """
|
|---|
| 32 |
|
|---|
| 33 | if hi is None:
|
|---|
| 34 | hi = len(a)
|
|---|
| 35 | while lo < hi:
|
|---|
| 36 | mid = (lo+hi)//2
|
|---|
| 37 | if x < a[mid]: hi = mid
|
|---|
| 38 | else: lo = mid+1
|
|---|
| 39 | return lo
|
|---|
| 40 |
|
|---|
| 41 | bisect = bisect_right # backward compatibility
|
|---|
| 42 |
|
|---|
| 43 | def insort_left(a, x, lo=0, hi=None):
|
|---|
| 44 | """Insert item x in list a, and keep it sorted assuming a is sorted.
|
|---|
| 45 |
|
|---|
| 46 | If x is already in a, insert it to the left of the leftmost x.
|
|---|
| 47 |
|
|---|
| 48 | Optional args lo (default 0) and hi (default len(a)) bound the
|
|---|
| 49 | slice of a to be searched.
|
|---|
| 50 | """
|
|---|
| 51 |
|
|---|
| 52 | if hi is None:
|
|---|
| 53 | hi = len(a)
|
|---|
| 54 | while lo < hi:
|
|---|
| 55 | mid = (lo+hi)//2
|
|---|
| 56 | if a[mid] < x: lo = mid+1
|
|---|
| 57 | else: hi = mid
|
|---|
| 58 | a.insert(lo, x)
|
|---|
| 59 |
|
|---|
| 60 |
|
|---|
| 61 | def bisect_left(a, x, lo=0, hi=None):
|
|---|
| 62 | """Return the index where to insert item x in list a, assuming a is sorted.
|
|---|
| 63 |
|
|---|
| 64 | The return value i is such that all e in a[:i] have e < x, and all e in
|
|---|
| 65 | a[i:] have e >= x. So if x already appears in the list, i points just
|
|---|
| 66 | before the leftmost x already there.
|
|---|
| 67 |
|
|---|
| 68 | Optional args lo (default 0) and hi (default len(a)) bound the
|
|---|
| 69 | slice of a to be searched.
|
|---|
| 70 | """
|
|---|
| 71 |
|
|---|
| 72 | if hi is None:
|
|---|
| 73 | hi = len(a)
|
|---|
| 74 | while lo < hi:
|
|---|
| 75 | mid = (lo+hi)//2
|
|---|
| 76 | if a[mid] < x: lo = mid+1
|
|---|
| 77 | else: hi = mid
|
|---|
| 78 | return lo
|
|---|
| 79 |
|
|---|
| 80 | # Overwrite above definitions with a fast C implementation
|
|---|
| 81 | try:
|
|---|
| 82 | from _bisect import bisect_right, bisect_left, insort_left, insort_right, insort, bisect
|
|---|
| 83 | except ImportError:
|
|---|
| 84 | pass
|
|---|
