結果
問題 |
No.1479 Matrix Eraser
|
ユーザー |
|
提出日時 | 2021-04-17 15:18:06 |
言語 | PyPy3 (7.3.15) |
結果 |
AC
|
実行時間 | 723 ms / 3,000 ms |
コード長 | 3,413 bytes |
コンパイル時間 | 170 ms |
コンパイル使用メモリ | 82,384 KB |
実行使用メモリ | 145,152 KB |
最終ジャッジ日時 | 2024-07-03 22:56:11 |
合計ジャッジ時間 | 18,021 ms |
ジャッジサーバーID (参考情報) |
judge5 / judge3 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 2 |
other | AC * 39 |
ソースコード
# Reference: https://tjkendev.github.io/procon-library/python/max_flow/dinic.html # Max Flow # 0-indexed from collections import deque from sys import setrecursionlimit setrecursionlimit(10**9) class Dinic: def __init__(self, n): self.n = n self.G = [[] for _ in range(n)] def add_edge(self, fr, to, cap): forward = [to, cap, None] forward[2] = backward = [fr, 0, forward] self.G[fr].append(forward) self.G[to].append(backward) def bfs(self, s, t): self.level = level = [None] * self.n deq = deque([s]) level[s] = 0 G = self.G while deq: v = deq.popleft() lv = level[v] + 1 for w, cap, _ in G[v]: if cap and level[w] is None: level[w] = lv deq.append(w) return level[t] is not None def dfs(self, v, t, f): if v == t: return f level = self.level for edge in self.it[v]: w, cap, rev = edge if cap and level[v] < level[w]: d = self.dfs(w, t, min(f, cap)) if d: edge[1] -= d rev[1] += d return d return 0 def flow(self, s, t, inf=1<<30): flow = 0 G = self.G while self.bfs(s, t): *self.it, = map(iter, self.G) f = inf while f: f = self.dfs(s, t, inf) flow += f return flow ### # Reference: https://www.slideshare.net/drken1215/ss-86894312 ### from collections import defaultdict from sys import stdin input = stdin.readline def main(): h, w = map(int, input().split()) a = [list(map(int, input().split())) for _ in range(h)] groups = defaultdict(list) for i in range(h): for j in range(w): groups[a[i][j]].append(w*i + j) if 0 in groups: groups.pop(0) ans = 0 for lis in groups.values(): rows = dict() columns = dict() for i in lis: if i//w not in rows: rows[i//w] = len(rows) if i%w not in columns: columns[i%w] = len(columns) # Max Flow # s >>> rows >>> columns >>> t s = len(rows)+len(columns) t = s + 1 mf = Dinic(t+1) for value in rows.values(): mf.add_edge(s, value, 1) for value in columns.values(): mf.add_edge(value+len(rows), t, 1) for i in lis: mf.add_edge(rows[i//w], columns[i%w]+len(rows), 1) mf.flow(s, t, len(lis)) edges = [[] for _ in range(s)] todo = [] for i in range(len(rows)): for j, cap, rev in mf.G[i]: if j == s or j == t: continue if rev[1]: edges[i].append(j) else: edges[j].append(i) todo.append(i) seen = [0] * s for start in todo: seen[start] = 1 while todo: i = todo.pop() for j in edges[i]: if seen[j]: continue seen[j] = 1 todo.append(j) ans += seen[:len(rows)].count(0) + seen[len(rows):].count(1) print(ans) main()