projects / OpenSPARC-T2-DV / blame
| Commit | Line | Data |
|---|---|---|
| 86530b38 AT |
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 |