結果

問題 No.2328 Build Walls
コンテスト
ユーザー gew1fw
提出日時 2025-06-12 20:19:40
言語 PyPy3
(7.3.15)
結果
MLE  
実行時間 -
コード長 3,804 bytes
コンパイル時間 238 ms
コンパイル使用メモリ 82,048 KB
実行使用メモリ 584,624 KB
最終ジャッジ日時 2025-06-12 20:20:25
合計ジャッジ時間 6,319 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge5
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 #
raw source code 

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()
        level[:] = [-1] * self.size
        level[s] = 0
        q.append(s)
        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, flow, level, ptr):
        if v == t:
            return flow
        while ptr[v] < len(self.graph[v]):
            edge = self.graph[v][ptr[v]]
            if edge.cap > 0 and level[v] < level[edge.to]:
                min_flow = min(flow, edge.cap)
                result = self.dfs_flow(edge.to, t, min_flow, level, ptr)
                if result > 0:
                    edge.cap -= result
                    self.graph[edge.to][edge.rev].cap += result
                    return result
            ptr[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
            ptr = [0] * self.size
            while True:
                f = self.dfs_flow(s, t, float('inf'), level, ptr)
                if f == 0:
                    break
                flow += f
            level = [-1] * self.size

def main():
    H, W = map(int, sys.stdin.readline().split())
    A = []
    for _ in range(H-2):
        A.append(list(map(int, sys.stdin.readline().split())))
    
    INF = 10**18
    num_cells = H * W
    in_node_base = 0
    out_node_base = in_node_base + num_cells
    S = out_node_base + num_cells
    T = S + 1
    total_nodes = T + 1
    
    dinic = Dinic(total_nodes)
    
    # Add in-out edges for each cell
    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 + num_cells
            if i == 1 or i == H:
                cap = INF
            else:
                if i < 2 or i > H-1:
                    cap = INF
                else:
                    a_ij = A[i-2][j-1]
                    if a_ij == -1:
                        cap = INF
                    else:
                        cap = a_ij
            dinic.add_edge(in_node, out_node, cap)
    
    # Add edges to adjacent cells
    directions = [ (-1,0), (1,0), (0,-1), (0,1) ]
    for i in range(1, H+1):
        for j in range(1, W+1):
            out_node = (i-1)*W + (j-1) + num_cells
            for di, dj in directions:
                ni = i + di
                nj = j + dj
                if 1 <= ni <= H and 1 <= nj <= W:
                    adj_in = (ni-1)*W + (nj-1)
                    dinic.add_edge(out_node, adj_in, INF)
    
    # Connect super-source S to in-nodes of first row
    for j in range(1, W+1):
        in_node = (0)*W + (j-1)
        dinic.add_edge(S, in_node, INF)
    
    # Connect out-nodes of last row to T
    for j in range(1, W+1):
        out_node = (H-1)*W + (j-1) + num_cells
        dinic.add_edge(out_node, T, INF)
    
    maxf = dinic.max_flow(S, T)
    if maxf >= INF:
        print(-1)
    else:
        print(maxf)

if __name__ == "__main__":
    main()
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