結果

問題 No.1813 Magical Stones
ユーザー MasKoaTSMasKoaTS
提出日時 2022-01-13 22:58:15
言語 Python3
(3.12.2 + numpy 1.26.4 + scipy 1.12.0)
結果
AC  
実行時間 1,730 ms / 2,000 ms
コード長 2,862 bytes
コンパイル時間 85 ms
コンパイル使用メモリ 12,928 KB
実行使用メモリ 69,928 KB
最終ジャッジ日時 2024-04-28 21:14:30
合計ジャッジ時間 28,678 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge4
このコードへのチャレンジ
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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 38 ms
11,776 KB
testcase_01 AC 41 ms
11,776 KB
testcase_02 AC 37 ms
11,776 KB
testcase_03 AC 482 ms
63,432 KB
testcase_04 AC 39 ms
11,648 KB
testcase_05 AC 38 ms
11,776 KB
testcase_06 AC 58 ms
14,208 KB
testcase_07 AC 38 ms
11,776 KB
testcase_08 AC 42 ms
12,288 KB
testcase_09 AC 46 ms
12,672 KB
testcase_10 AC 42 ms
12,160 KB
testcase_11 AC 320 ms
29,212 KB
testcase_12 AC 37 ms
11,776 KB
testcase_13 AC 37 ms
11,776 KB
testcase_14 AC 498 ms
63,308 KB
testcase_15 AC 1,538 ms
69,872 KB
testcase_16 AC 1,502 ms
69,660 KB
testcase_17 AC 1,333 ms
62,044 KB
testcase_18 AC 1,496 ms
69,792 KB
testcase_19 AC 1,541 ms
69,920 KB
testcase_20 AC 1,555 ms
69,660 KB
testcase_21 AC 1,730 ms
69,648 KB
testcase_22 AC 1,518 ms
69,928 KB
testcase_23 AC 1,509 ms
69,660 KB
testcase_24 AC 47 ms
12,416 KB
testcase_25 AC 206 ms
22,528 KB
testcase_26 AC 75 ms
15,360 KB
testcase_27 AC 1,054 ms
55,124 KB
testcase_28 AC 1,137 ms
48,424 KB
testcase_29 AC 1,204 ms
57,144 KB
testcase_30 AC 1,052 ms
53,392 KB
testcase_31 AC 1,372 ms
67,512 KB
testcase_32 AC 38 ms
11,776 KB
testcase_33 AC 36 ms
11,648 KB
testcase_34 AC 67 ms
13,440 KB
testcase_35 AC 145 ms
15,744 KB
testcase_36 AC 58 ms
14,080 KB
testcase_37 AC 320 ms
21,056 KB
testcase_38 AC 389 ms
45,580 KB
testcase_39 AC 1,032 ms
57,096 KB
testcase_40 AC 59 ms
13,696 KB
testcase_41 AC 64 ms
12,928 KB
testcase_42 AC 146 ms
15,872 KB
testcase_43 AC 107 ms
15,488 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 # 

import itertools as iter
import collections as coll
import heapq as hq
import bisect as bis
from decimal import Decimal as dec
from copy import deepcopy as dcopy
import math
import sys
sys.setrecursionlimit(10**6)
def input():
    return sys.stdin.readline().rstrip()
def getN():
	return int(sys.stdin.readline())
def getNs():
	return map(int,sys.stdin.readline().split())
def getList():
	return list(map(int,sys.stdin.readline().split()))
def strinps(n):
	return [sys.stdin.readline().rstrip() for _ in range(n)]
pi = 3.141592653589793
mod = 10**9+7
MOD = 998244353
INF = math.inf
dx = [1,0,-1,0];	dy = [0,1,0,-1]

"""
強連結成分分解（SCC）
from : https://github.com/ryusuke920/kyopro_educational_90_python/blob/main/solve_python/021.py
ref : https://manabitimes.jp/math/1250
"""

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
	
	#グラフに有向辺を追加（逆向きのものを含む）
	def add_edge(self, v, nxt_v):
		self.graph[v].append(nxt_v)
		self.rev_graph[nxt_v].append(v)

	#SCCグラフの構成
	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

	#SCCグラフを作る上でのDFS
	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())

	#逆向きDFS
	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

	#構成し終えたSCCグラフを連結成分ごとにリストにする
	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 = getNs()
route = [[] for _ in [0] * n]
scc = SCC(n)
for _ in [0] * m:
	a,b = [i - 1 for i in getNs()]
	route[a].append(b)
	scc.add_edge(a,b)
scc.build()
dag, _ = scc.construct()

s = len(dag)
if(s == 1):
	print(0)
	exit(0)

source = [True] * s
sink = [True] * s
for i in range(s):
	for j in dag[i]:
		sink[i] = source[j] = False
print(max(sum(source), sum(sink)))
0