205 . 有向圖拆解

Submit
Status
Discussion / Solution
Ranklist
Back to Problems List

TopCoder

abcabcabc

User's AC Ratio

100.0% (2/2)

Submission's AC Ratio

100.0% (4/4)

Tags

ioicamp ioicamp-2021

Description

給定一個 $N$ 點 $M$ 邊的有向圖，請將它拆成若干個有向環或有向鍊，且每個節點都在恰一個部分上。在所有可能的拆法下，請找出一個鍊最少的拆法。

Input Format

輸入第一行有兩個整數 $N$ 與 $M$，代表點數與邊數。

接著 $M$ 行，第 $i$ 行有兩個正整數 $u_i$ 與 $v_i$ ，代表圖中有一條 $u_i$ 到 $v_i$ 的有向邊。

  • $1 \leq N \leq 500$
  • $0 \leq M \leq N \times (N - 1)$
  • $1 \leq u_i, v_i \leq N, u_i \neq v_i$
  • 保證每條有向邊只會出現至多一次

Output Format

請輸出一行，該行有一個數字代表最少需要幾條鍊。

Sample Input 1

3 3
1 2
2 3
3 1

Sample Output 1

0

Sample Input 2

3 2
1 2
2 3

Sample Output 2

1

Sample Input 3

3 0

Sample Output 3

3

Hints

Problem Source

IOICamp 2021 Day2 pE

Subtasks

No. Testdata Range Constraints Score
1 0~2 範例測資 0
2 0~129 無額外限制 100

Testdata and Limits

No. Time Limit (ms) Memory Limit (VSS, KiB) Output Limit (KiB) Subtasks
0 1000 262144 65536 1 2
1 1000 262144 65536 1 2
2 1000 262144 65536 1 2
3 1000 262144 65536 2
4 1000 262144 65536 2
5 1000 262144 65536 2
6 1000 262144 65536 2
7 1000 262144 65536 2
8 1000 262144 65536 2
9 1000 262144 65536 2
10 1000 262144 65536 2
11 1000 262144 65536 2
12 1000 262144 65536 2
13 1000 262144 65536 2
14 1000 262144 65536 2
15 1000 262144 65536 2
16 1000 262144 65536 2
17 1000 262144 65536 2
18 1000 262144 65536 2
19 1000 262144 65536 2
20 1000 262144 65536 2
21 1000 262144 65536 2
22 1000 262144 65536 2
23 1000 262144 65536 2
24 1000 262144 65536 2
25 1000 262144 65536 2
26 1000 262144 65536 2
27 1000 262144 65536 2
28 1000 262144 65536 2
29 1000 262144 65536 2
30 1000 262144 65536 2
31 1000 262144 65536 2
32 1000 262144 65536 2
33 1000 262144 65536 2
34 1000 262144 65536 2
35 1000 262144 65536 2
36 1000 262144 65536 2
37 1000 262144 65536 2
38 1000 262144 65536 2
39 1000 262144 65536 2
40 1000 262144 65536 2
41 1000 262144 65536 2
42 1000 262144 65536 2
43 1000 262144 65536 2
44 1000 262144 65536 2
45 1000 262144 65536 2
46 1000 262144 65536 2
47 1000 262144 65536 2
48 1000 262144 65536 2
49 1000 262144 65536 2
50 1000 262144 65536 2
51 1000 262144 65536 2
52 1000 262144 65536 2
53 1000 262144 65536 2
54 1000 262144 65536 2
55 1000 262144 65536 2
56 1000 262144 65536 2
57 1000 262144 65536 2
58 1000 262144 65536 2
59 1000 262144 65536 2
60 1000 262144 65536 2
61 1000 262144 65536 2
62 1000 262144 65536 2
63 1000 262144 65536 2
64 1000 262144 65536 2
65 1000 262144 65536 2
66 1000 262144 65536 2
67 1000 262144 65536 2
68 1000 262144 65536 2
69 1000 262144 65536 2
70 1000 262144 65536 2
71 1000 262144 65536 2
72 1000 262144 65536 2
73 1000 262144 65536 2
74 1000 262144 65536 2
75 1000 262144 65536 2
76 1000 262144 65536 2
77 1000 262144 65536 2
78 1000 262144 65536 2
79 1000 262144 65536 2
80 1000 262144 65536 2
81 1000 262144 65536 2
82 1000 262144 65536 2
83 1000 262144 65536 2
84 1000 262144 65536 2
85 1000 262144 65536 2
86 1000 262144 65536 2
87 1000 262144 65536 2
88 1000 262144 65536 2
89 1000 262144 65536 2
90 1000 262144 65536 2
91 1000 262144 65536 2
92 1000 262144 65536 2
93 1000 262144 65536 2
94 1000 262144 65536 2
95 1000 262144 65536 2
96 1000 262144 65536 2
97 1000 262144 65536 2
98 1000 262144 65536 2
99 1000 262144 65536 2
100 1000 262144 65536 2
101 1000 262144 65536 2
102 1000 262144 65536 2
103 1000 262144 65536 2
104 1000 262144 65536 2
105 1000 262144 65536 2
106 1000 262144 65536 2
107 1000 262144 65536 2
108 1000 262144 65536 2
109 1000 262144 65536 2
110 1000 262144 65536 2
111 1000 262144 65536 2
112 1000 262144 65536 2
113 1000 262144 65536 2
114 1000 262144 65536 2
115 1000 262144 65536 2
116 1000 262144 65536 2
117 1000 262144 65536 2
118 1000 262144 65536 2
119 1000 262144 65536 2
120 1000 262144 65536 2
121 1000 262144 65536 2
122 1000 262144 65536 2
123 1000 262144 65536 2
124 1000 262144 65536 2
125 1000 262144 65536 2
126 1000 262144 65536 2
127 1000 262144 65536 2
128 1000 262144 65536 2
129 1000 262144 65536 2
Submit
Back to Top