File size: 11,488 Bytes
d966228 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 | """
Span merger: given a list of valid line numbers and a list of possible spans,
produce a list of output spans that accounts for every line number.
Assignment rules
----------------
Each line number is assigned to the span(s) closest to it:
distance(line l, span [a, b]) = max(0, a − l, l − b)
= 0 if the line is inside the span,
a − l if the line is left of the span,
l − b if the line is right of the span.
A line is assigned to *every* span that achieves the minimum distance.
When a line is equidistant between two adjacent spans both spans claim it
at assignment time.
Tie-breaking at span boundaries
-------------------------------
For a given span's intermediate output [start, end]:
• start (1st element) – when multiple assigned lines are tied as closest
to the span's nominal left boundary, the *smallest* is chosen (biased left).
• end (2nd element) – when multiple assigned lines are tied as closest
to the span's nominal right boundary, the *largest* is chosen (biased right).
Because the intermediate boundaries are simply min / max of the assigned
lines these tie-breaking rules are satisfied automatically.
Output normalization
--------------------
The returned spans are normalized after assignment:
• If two consecutive outputs touch at exactly one duplicated boundary
point, the earlier span is shrunk so the final output stays disjoint.
• If candidate spans overlap enough to create a genuine overlap in the
output, those overlapping outputs are merged.
Special cases
-------------
• Empty line list → empty output.
• No possible spans → all lines emitted as one ``missing`` span.
• Spans with no lines assigned to them are omitted from the output.
"""
from __future__ import annotations
from typing import TypedDict
class SpanResult(TypedDict):
start: int
end: int
missing: bool
def _distance_to_span(line: int, start: int, end: int) -> int:
return max(0, start - line, line - end)
def _normalize_spans(possible_spans: list[list[int]]) -> list[tuple[int, int]]:
normalized: list[tuple[int, int]] = []
for idx, span in enumerate(possible_spans):
if len(span) != 2:
raise ValueError(f"span at index {idx} must contain exactly two integers")
start, end = span
if not isinstance(start, int) or not isinstance(end, int):
raise TypeError(f"span at index {idx} must contain integers")
if start > end:
raise ValueError(
f"span at index {idx} has start > end: [{start}, {end}]"
)
normalized.append((start, end))
return sorted(normalized, key=lambda span: (span[0], span[1]))
def merge_spans(
line_numbers: list[int],
possible_spans: list[list[int]],
) -> list[SpanResult]:
"""
Parameters
----------
line_numbers:
Unsorted / duplicate-containing list of valid line numbers.
possible_spans:
List of [start, end] inclusive span boundaries.
Returns
-------
List of dicts ``{'start': int, 'end': int, 'missing': bool}``,
ordered by start position.
Each line is assigned to the span(s) with the smallest
``max(0, a − l, l − b)`` distance. Lines equidistant between two
adjacent spans are claimed by *both* at assignment time. The final
returned spans are normalized so the output does not contain a
duplicated boundary point, and any genuine overlap caused by
overlapping candidate spans is merged.
The output start / end of each span is the min / max of its assigned
lines, which automatically implements the tie-breaking rule:
start biased toward smaller values, end toward larger values.
Raises
------
ValueError
If any span does not contain exactly two integers or if ``start > end``.
TypeError
If any span boundary is not an integer.
"""
sorted_lines = sorted(set(line_numbers))
spans = _normalize_spans(possible_spans)
if not sorted_lines:
return []
if not spans:
return [{"start": sorted_lines[0], "end": sorted_lines[-1], "missing": True}]
assignments: list[list[int]] = [[] for _ in spans]
for line in sorted_lines:
min_dist = min(_distance_to_span(line, start, end) for start, end in spans)
for idx, (start, end) in enumerate(spans):
if _distance_to_span(line, start, end) == min_dist:
assignments[idx].append(line)
output: list[SpanResult] = []
out_assignments: list[list[int]] = []
for assigned in assignments:
if assigned:
output.append({"start": assigned[0], "end": assigned[-1], "missing": False})
out_assignments.append(assigned)
i = 0
while i < len(output) - 1:
if output[i]["end"] == output[i + 1]["start"]:
overlap = output[i]["end"]
smaller = [line for line in out_assignments[i] if line < overlap]
if smaller:
output[i]["end"] = smaller[-1]
i += 1
else:
output.pop(i)
out_assignments.pop(i)
else:
i += 1
i = 0
while i < len(output) - 1:
if output[i]["end"] >= output[i + 1]["start"]:
output[i] = {
"start": output[i]["start"],
"end": max(output[i]["end"], output[i + 1]["end"]),
"missing": output[i]["missing"] or output[i + 1]["missing"],
}
output.pop(i + 1)
else:
i += 1
return output
# --------------------------------------------------------------------------- #
# Formatting helper #
# --------------------------------------------------------------------------- #
def format_spans(spans: list[SpanResult]) -> str:
parts = []
for s in spans:
tag = f"[{s['start']},{s['end']}]"
parts.append(tag)
return "[" + ", ".join(parts) + "]"
# --------------------------------------------------------------------------- #
# Smoke-tests #
# --------------------------------------------------------------------------- #
if __name__ == "__main__":
cases = [
# ── Original examples ──────────────────────────────────────────── #
{
"label": "Example 1 – pre-line absorbed into nearest span; empty span dropped",
"lines": [1, 3, 5, 6, 7, 8, 9, 10, 12, 15],
"spans": [[2, 5], [6, 15], [16, 20]],
"expected": "[[1,5], [6,15]]",
},
{
"label": "Example 2 – line 5 equidistant → prev span end shrunk from 5→3",
"lines": [1, 3, 5, 6, 7, 8, 9, 10, 12, 18],
"spans": [[2, 4], [6, 14], [16, 20]],
"expected": "[[1,3], [5,12], [18,18]]",
},
# ── Edge cases ─────────────────────────────────────────────────── #
{
"label": "EC-01 empty line list → empty output",
"lines": [],
"spans": [[1, 5], [6, 10]],
"expected": "[]",
},
{
"label": "EC-02 no spans → all lines become missing groups",
# Bug: the old else-branch would double-emit everything.
"lines": [2, 3, 7, 8],
"spans": [],
"expected": "[[2,8]]",
},
{
"label": "EC-03 all lines left of only span → absorbed as nearest",
"lines": [1, 2, 3],
"spans": [[10, 20]],
"expected": "[[1,3]]",
},
{
"label": "EC-04 all lines right of only span → absorbed as nearest",
"lines": [15, 16, 20],
"spans": [[1, 10]],
"expected": "[[15,20]]",
},
{
"label": "EC-05 adjacent spans → each line goes to the span it is inside",
"lines": [1, 3, 5, 8],
"spans": [[1, 4], [5, 10]],
"expected": "[[1,3], [5,8]]",
},
{
"label": "EC-06 duplicate line numbers → deduplicated before processing",
"lines": [3, 3, 5, 5, 7],
"spans": [[1, 10]],
"expected": "[[3,7]]",
},
{
"label": "EC-07 line 7 equidistant → prev span end shrunk from 7→3",
"lines": [3, 7, 11],
"spans": [[1, 5], [9, 15]],
"expected": "[[3,3], [7,11]]",
},
{
"label": "EC-08 empty gap → each line assigned to the span it is inside, no overlap",
"lines": [2, 4, 8, 12],
"spans": [[1, 5], [7, 15]],
"expected": "[[2,4], [8,12]]",
},
{
"label": "EC-09 single line, span wider than needed → clipped at line",
"lines": [5],
"spans": [[3, 7]],
"expected": "[[5,5]]",
},
{
"label": "EC-10 line 6 equidistant → prev span end shrunk from 6→2",
"lines": [2, 6, 7, 11, 15],
"spans": [[1, 4], [8, 12], [14, 20]],
"expected": "[[2,2], [6,11], [15,15]]",
},
{
"label": "EC-11 single span → all lines (pre and inside) absorbed as nearest",
"lines": [1, 2, 5, 6, 15],
"spans": [[10, 20]],
"expected": "[[1,15]]",
},
{
"label": "EC-12 first span gets no lines; subsequent spans absorb orphans",
"lines": [3, 8],
"spans": [[1, 2], [5, 7], [10, 15]],
"expected": "[[3,3], [8,8]]",
},
{
"label": "EC-13 line 10 equidistant → prev span end shrunk from 10→5",
"lines": [1, 5, 10, 15, 20],
"spans": [[3, 8], [12, 18]],
"expected": "[[1,5], [10,20]]",
},
{
"label": "EC-14 overlap where prev span has no smaller line → prev span dropped",
# line 7 equidistant between [1,5] and [9,15]: both claim it.
# span 0 assigned=[7] only; no line < 7 exists → span 0 is dropped.
"lines": [7, 11],
"spans": [[1, 5], [9, 15]],
"expected": "[[7,11]]",
},
{
"label": "EC-15 overlapping possible spans → genuine overlap merged in pass 2",
# spans [1,8] and [3,10] overlap; lines 4 and 6 are inside both →
# both spans claim 4 and 6, so output before pass 2 = [[2,6],[4,9]].
# pass 1 sees 6 != 4 (strict >), skips; pass 2 merges → [[2,9]].
"lines": [2, 4, 6, 9],
"spans": [[1, 8], [3, 10]],
"expected": "[[2,9]]",
},
]
for case in cases:
result = merge_spans(case["lines"], case["spans"])
formatted = format_spans(result)
status = "✓" if formatted == case["expected"] else "✗"
print(f"{status} {case['label']}")
print(f" lines: {case['lines']}")
print(f" spans: {case['spans']}")
print(f" output: {formatted}")
print(f" expected: {case['expected']}")
print()
|