結果

問題 No.2328 Build Walls
ユーザー lam6er
提出日時 2025-03-20 20:23:09
言語 PyPy3
(7.3.15)
結果
MLE  
実行時間 -
コード長 3,195 bytes
コンパイル時間 144 ms
コンパイル使用メモリ 82,380 KB
実行使用メモリ 556,992 KB
最終ジャッジ日時 2025-03-20 20:25:08
合計ジャッジ時間 6,084 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge3
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 10 MLE * 1 -- * 23
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 # 

import sys
from collections import deque

class Edge:
    def __init__(self, to, rev, cap):
        self.to = to
        self.rev = rev
        self.cap = cap

class Dinic:
    def __init__(self, n):
        self.size = n
        self.graph = [[] for _ in range(n)]
    
    def add_edge(self, fr, to, cap):
        forward = Edge(to, len(self.graph[to]), cap)
        backward = Edge(fr, len(self.graph[fr]), 0)
        self.graph[fr].append(forward)
        self.graph[to].append(backward)
    
    def bfs_level(self, s, t, level):
        q = deque([s])
        level[:] = [-1] * self.size
        level[s] = 0
        while q:
            v = q.popleft()
            for edge in self.graph[v]:
                if edge.cap > 0 and level[edge.to] == -1:
                    level[edge.to] = level[v] + 1
                    q.append(edge.to)
                    if edge.to == t:
                        return
    
    def dfs_flow(self, v, t, upTo, iter_, level):
        if v == t:
            return upTo
        for i in range(iter_[v], len(self.graph[v])):
            edge = self.graph[v][i]
            if edge.cap > 0 and level[v] < level[edge.to]:
                d = self.dfs_flow(edge.to, t, min(upTo, edge.cap), iter_, level)
                if d > 0:
                    edge.cap -= d
                    self.graph[edge.to][edge.rev].cap += d
                    return d
            iter_[v] += 1
        return 0
    
    def max_flow(self, s, t):
        flow = 0
        level = [-1] * self.size
        while True:
            self.bfs_level(s, t, level)
            if level[t] == -1:
                return flow
            iter_ = [0] * self.size
            while True:
                f = self.dfs_flow(s, t, float('inf'), iter_, level)
                if f == 0:
                    break
                flow += f
        return flow

def main():
    H, W = map(int, sys.stdin.readline().split())
    rows = H - 2
    A = []
    for _ in range(rows):
        A.append(list(map(int, sys.stdin.readline().split())))
    
    INF = 1 << 60
    node_num = 2 * H * W + 2
    S = 2 * H * W
    T = S + 1
    dinic = Dinic(node_num)
    
    for i in range(1, H + 1):
        for j in range(1, W + 1):
            in_node = (i - 1) * W + (j - 1)
            out_node = in_node + H * W
            if i == 1 or i == H:
                cap = INF
            else:
                a = A[i - 2][j - 1]
                cap = INF if a == -1 else a
            dinic.add_edge(in_node, out_node, cap)
            
            dirs = [(-1, 0), (1, 0), (0, -1), (0, 1)]
            for di, dj in dirs:
                ni, nj = i + di, j + dj
                if 1 <= ni <= H and 1 <= nj <= W:
                    next_in = (ni - 1) * W + (nj - 1)
                    dinic.add_edge(out_node, next_in, INF)
    
    for j in range(1, W + 1):
        i = 1
        out_node = ((i - 1) * W + (j - 1)) + H * W
        dinic.add_edge(S, out_node, INF)
    
    for j in range(1, W + 1):
        i = H
        in_node = (i - 1) * W + (j - 1)
        dinic.add_edge(in_node, T, INF)
    
    mf = dinic.max_flow(S, T)
    print(-1 if mf >= INF else mf)

if __name__ == '__main__':
    main()
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