結果

問題 No.1813 Magical Stones
ユーザー MasKoaTSMasKoaTS
提出日時 2021-09-19 13:02:22
言語 Python3
(3.12.2 + numpy 1.26.4 + scipy 1.12.0)
結果
AC  
実行時間 1,493 ms / 2,000 ms
コード長 1,906 bytes
コンパイル時間 729 ms
コンパイル使用メモリ 11,084 KB
実行使用メモリ 56,368 KB
最終ジャッジ日時 2023-09-23 07:02:48
合計ジャッジ時間 28,668 ms
ジャッジサーバーID
（参考情報） 		judge11 / judge13
このコードへのチャレンジ（β）

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 17 ms
8,448 KB
testcase_01 AC 17 ms
8,432 KB
testcase_02 AC 17 ms
8,500 KB
testcase_03 AC 365 ms
53,248 KB
testcase_04 AC 17 ms
8,360 KB
testcase_05 AC 17 ms
8,404 KB
testcase_06 AC 39 ms
10,544 KB
testcase_07 AC 18 ms
8,500 KB
testcase_08 AC 21 ms
8,828 KB
testcase_09 AC 23 ms
9,128 KB
testcase_10 AC 21 ms
8,864 KB
testcase_11 AC 259 ms
23,592 KB
testcase_12 AC 17 ms
8,428 KB
testcase_13 AC 17 ms
8,396 KB
testcase_14 AC 361 ms
53,324 KB
testcase_15 AC 1,490 ms
56,368 KB
testcase_16 AC 1,491 ms
56,300 KB
testcase_17 AC 1,407 ms
47,784 KB
testcase_18 AC 1,484 ms
56,304 KB
testcase_19 AC 1,493 ms
56,368 KB
testcase_20 AC 1,467 ms
56,280 KB
testcase_21 AC 1,459 ms
56,280 KB
testcase_22 AC 1,477 ms
56,248 KB
testcase_23 AC 1,483 ms
56,304 KB
testcase_24 AC 28 ms
8,932 KB
testcase_25 AC 151 ms
17,784 KB
testcase_26 AC 58 ms
11,680 KB
testcase_27 AC 1,000 ms
44,340 KB
testcase_28 AC 1,213 ms
38,484 KB
testcase_29 AC 1,255 ms
45,780 KB
testcase_30 AC 1,169 ms
42,732 KB
testcase_31 AC 1,369 ms
54,548 KB
testcase_32 AC 17 ms
8,492 KB
testcase_33 AC 18 ms
8,408 KB
testcase_34 AC 54 ms
9,920 KB
testcase_35 AC 174 ms
11,824 KB
testcase_36 AC 36 ms
10,548 KB
testcase_37 AC 368 ms
16,348 KB
testcase_38 AC 288 ms
37,712 KB
testcase_39 AC 937 ms
46,268 KB
testcase_40 AC 41 ms
10,204 KB
testcase_41 AC 58 ms
9,452 KB
testcase_42 AC 185 ms
12,112 KB
testcase_43 AC 102 ms
11,596 KB
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 # 

class SCC:
	def __init__(self, n):
		self.n = n
		self.graph = [[] for _ in range(n)]
		self.rev_graph = [[] for _ in range(n)]
		self.labels = [-1] * n
		self.lb_cnt = 0
	
	def add_edge(self, v, nxt_v):
		self.graph[v].append(nxt_v)
		self.rev_graph[nxt_v].append(v)

	def build(self):
		self.post_order = []
		self.used = [False] * self.n
		for v in range(self.n):
			if(not self.used[v]):
				self._dfs(v)
		for v in reversed(self.post_order):
			if(self.labels[v] == -1):
				self._rev_dfs(v)
				self.lb_cnt += 1

	def _dfs(self, v):
		stack = [v, 0]
		while(stack):
			v, idx = stack[-2:]
			if not idx and self.used[v]:
				stack.pop()
				stack.pop()
			else:
				self.used[v] = True
				if idx < len(self.graph[v]):
					stack[-1] += 1
					stack.append(self.graph[v][idx])
					stack.append(0)
				else:
					stack.pop()
					self.post_order.append(stack.pop())

	def _rev_dfs(self, v):
		stack = [v]
		self.labels[v] = self.lb_cnt
		while stack:
			v = stack.pop()
			for nxt_v in self.rev_graph[v]:
				if self.labels[nxt_v] != -1:
					continue
				stack.append(nxt_v)
				self.labels[nxt_v] = self.lb_cnt

	def construct(self):
		self.dag = [[] for i in range(self.lb_cnt)]
		self.groups = [[] for i in range(self.lb_cnt)]
		for v, lb in enumerate(self.labels):
			for nxt_v in self.graph[v]:
				nxt_lb = self.labels[nxt_v]
				if lb == nxt_lb:
					continue
				self.dag[lb].append(nxt_lb)
			self.groups[lb].append(v)
		return self.dag, self.groups


"""
Main Code
"""

n,m = map(int,input().split())

scc = SCC(n)
for _ in range(m):
    a,b = map(int,input().split())
    scc.add_edge(a-1,b-1)
scc.build()

DAG,_ = scc.construct()
t = len(DAG)

if(t <= 1):
	print(0)
	exit(0)

source = [True]*t
sink = [True]*t
for i in range(t):
	for j in DAG[i]:
		sink[i] = source[j] = False
source_cnt = sum(i for i in source)
sink_cnt = sum(i for i in sink)
ans = max(source_cnt,sink_cnt)

print(ans)
0