結果

問題 No.1479 Matrix Eraser
コンテスト
ユーザー eijirou
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
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 * 2
other AC * 39
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 # 

# 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()
0