結果

問題 No.1301 Strange Graph Shortest Path
ユーザー aaaaaaaaaa2230aaaaaaaaaa2230
提出日時 2021-03-09 11:12:09
言語 PyPy3
(7.3.15)
結果
WA  
実行時間 -
コード長 3,569 bytes
コンパイル時間 251 ms
コンパイル使用メモリ 82,824 KB
実行使用メモリ 150,784 KB
最終ジャッジ日時 2024-04-19 09:15:25
合計ジャッジ時間 15,332 ms
ジャッジサーバーID
（参考情報） 		judge5 / judge2
このコードへのチャレンジ
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テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 41 ms
53,248 KB
testcase_01 AC 39 ms
53,376 KB
testcase_02 WA -
testcase_03 WA -
testcase_04 WA -
testcase_05 WA -
testcase_06 WA -
testcase_07 WA -
testcase_08 WA -
testcase_09 WA -
testcase_10 WA -
testcase_11 WA -
testcase_12 WA -
testcase_13 WA -
testcase_14 WA -
testcase_15 WA -
testcase_16 WA -
testcase_17 WA -
testcase_18 WA -
testcase_19 WA -
testcase_20 WA -
testcase_21 WA -
testcase_22 WA -
testcase_23 WA -
testcase_24 WA -
testcase_25 WA -
testcase_26 WA -
testcase_27 WA -
testcase_28 WA -
testcase_29 WA -
testcase_30 WA -
testcase_31 WA -
testcase_32 AC 38 ms
53,828 KB
testcase_33 AC 414 ms
144,048 KB
testcase_34 WA -
権限があれば一括ダウンロードができます

ソースコード

diff # 

from heapq import heappush, heappop
class mincostflow:

    class edge:
        def __init__(self, from_, to, cap, flow, cost):
            self.from_ = from_
            self.to = to
            self.cap = cap
            self.flow = flow
            self.cost = cost
    class _edge:
        def __init__(self, to, rev, cap, cost):
            self.to = to
            self.rev = rev
            self.cap = cap
            self.cost = cost

    def __init__(self, n):
        self.n = n
        self.pos = []
        self.g = [[] for i in range(n)]

    def add_edge(self, from_, to, cap, cost):
        m = len(self.pos)
        self.pos.append((from_, len(self.g[from_])))
        self.g[from_].append(self.__class__._edge(to, len(self.g[to]), cap, cost))
        self.g[to].append(self.__class__._edge(from_, len(self.g[from_])-1, 0, -cost))
        return m

    def get_edge(self, i):
        _e = self.g[self.pos[i][0]][self.pos[i][1]]
        _re = self.g[_e.to][_e.rev]
        return self.edge(self.pos[i][0], _e.to, _e.cap + _re.cap, _re.cap, _e.cost)

    def edges(self):
        result = []
        for i in range(len(self.pos)):
            result.append(self.get_edge(i))
        return result

    def slope(self, s, t, flow_limit=10**20, inf=10**20):
        dual = [0]*self.n
        dist = [inf]*self.n
        pv = [-1]*self.n
        pe = [-1]*self.n
        vis = [False]*self.n

        def _dual_ref():
            nonlocal dual, dist, pv, pe, vis
            dist = [inf]*self.n
            pv = [-1]*self.n
            pe = [-1]*self.n
            vis = [False]*self.n

            que = [(0,s)]
            dist[s] = 0
            while que:
                _,v = heappop(que)
                if vis[v]:
                    continue
                vis[v] = True

                if v == t:
                    break
                for i in range(len(self.g[v])):
                    e = self.g[v][i]
                    if vis[e.to] or e.cap == 0:
                        continue
                    cost = e.cost - dual[e.to] + dual[v]
                    if dist[e.to] > dist[v] + cost:
                        dist[e.to] = dist[v] + cost
                        pv[e.to] = v
                        pe[e.to] = i
                        heappush(que, (dist[e.to],e.to))
            if not vis[t]:
                return False

            for v in range(self.n):
                if not vis[v]:
                    continue
                dual[v] -= dist[t] - dist[v]
            return True
        
        flow = 0
        cost = 0
        prev_cost = -1

        result = [(flow, cost)]
        while flow < flow_limit:
            if not _dual_ref():
                break
            c = flow_limit - flow
            v = t
            while v != s:
                c = min(c, self.g[pv[v]][pe[v]].cap)
                v = pv[v]

            v = t
            while v != s:
                e = self.g[pv[v]][pe[v]]
                e.cap -= c
                self.g[v][e.rev].cap += c
                v = pv[v]
            
            d = -dual[s]
            flow += c
            cost += c * d
            if prev_cost == d:
                result.pop()
            result.append((flow, cost))
            prev_cost = cost
        return result

    def flow(self, s, t, flow_limit=10**20):
        return self.slope(s, t, flow_limit)[-1]
    
n,m = map(int,input().split())

g = mincostflow(n+1)
for i in range(m):
    u,v,c,d = map(int,input().split())
    g.add_edge(u,v,1,c)
    g.add_edge(u,v,1,d)

print(g.flow(1,n,2)[1])
0