两份锁差在哪

（每道题开头都有同一段：parse_ver 把「1.4.0」变成能比大小的元组，satisfies(版本, 约束) 判一个版本满不满足「>=1.4,<2」这种约束，split_req 把「httpkit>=1.4」切成名字和约束；REPO 是上面那个小仓库。）

（candidates 列出仓库里满足约束的版本（从低到高）；resolve(清单) 逐个选最高可用版本、把它的依赖加进队列、约束越收越紧，交回 {包: 版本}，无解交回 None。它不回溯——pip 会。）

（这一节多了：parse_requirements 读清单文本（跳过空行和 # 注释），freeze 把选好的版本写成锁文件文本，parse_lock 读回来，diff_lock 比两份锁。）

A 机器和 B 机器各交了一份锁。比一比：

def parse_ver(s):
    return tuple(int(x) for x in s.split("."))


def satisfies(ver, spec):
    v = parse_ver(ver)
    for part in spec.split(","):
        part = part.strip()
        if not part:
            continue
        for op in (">=", "<=", "==", "!=", ">", "<"):
            if part.startswith(op):
                w = parse_ver(part[len(op):])
                break
        ok = {">=": v >= w, "<=": v <= w, "==": v == w, "!=": v != w, ">": v > w, "<": v < w}[op]
        if not ok:
            return False
    return True


def split_req(line):
    i = 0
    while i < len(line) and (line[i].isalnum() or line[i] in "_-"):
        i += 1
    return line[:i], line[i:].replace(" ", "")


REPO = {
    "urlkit":  {"1.9.0": [], "2.0.0": [], "2.1.0": []},
    "charkit": {"4.0.0": [], "5.1.0": []},
    "httpkit": {"1.3.0": ["urlkit<2", "charkit<5"], "1.4.0": ["urlkit<2", "charkit>=4"], "1.5.0": ["urlkit>=2", "charkit>=5"]},
    "templ":   {"3.0.0": [], "3.1.0": []},
    "webapp":  {"2.3.0": ["httpkit>=1.3,<1.5", "templ>=3"], "3.0.0": ["httpkit>=1.5", "templ>=3.1"]},
}


def candidates(name, spec):
    return sorted((v for v in REPO.get(name, {}) if satisfies(v, spec)), key=parse_ver)


def resolve(reqs):
    spec = {}
    for r in reqs:
        n, s = split_req(r)
        spec[n] = s if n not in spec else spec[n] + "," + s
    chosen = {}
    todo = list(spec)
    while todo:
        n = todo.pop(0)
        cands = candidates(n, spec.get(n, ""))
        if not cands:
            return None
        v = cands[-1]
        if chosen.get(n) == v:
            continue
        chosen[n] = v
        for d in REPO[n][v]:
            dn, ds = split_req(d)
            spec[dn] = ds if dn not in spec else spec[dn] + "," + ds
            todo.append(dn)
    for n, v in chosen.items():
        if not satisfies(v, spec[n]):
            return None
    return chosen


def parse_requirements(text):
    reqs = []
    for line in text.split("\n"):
        line = line.split("#")[0].strip()
        if line:
            reqs.append(line)
    return reqs


def freeze(chosen):
    return "\n".join(n + "==" + chosen[n] for n in sorted(chosen))


def parse_lock(text):
    lock = {}
    for line in parse_requirements(text):
        n, s = split_req(line)
        lock[n] = s[2:]
    return lock


def diff_lock(a, b):
    changed = sorted(n for n in a if n in b and a[n] != b[n])
    added = sorted(n for n in b if n not in a)
    removed = sorted(n for n in a if n not in b)
    return changed, added, removed

a = parse_lock("charkit==5.1.0\nhttpkit==1.4.0\ntempl==3.1.0\nurlkit==1.9.0\nwebapp==2.3.0\n")
b = parse_lock("charkit==5.1.0\nhttpkit==1.5.0\ntempl==3.1.0\nurlkit==2.1.0\nwebapp==3.0.0\nextra==0.1.0\n")
changed, added, removed = diff_lock(a, b)
print(",".join(changed) + "/" + ",".join(added) + "/" + str(len(removed)))