Good test:

16
0 0
3 0
3 1
4 1
4 0
7 0
7 2
6 2
6 1
5 1
5 2
2 2
2 1
1 1
1 2
0 2

My AC program prints 7.000000

Another test:

13
1 1
3 1
3 3
5 3
5 5
3 5
4 4
2 4
2 2
1 3
0 3
0 0
1 0

Answer:
7.071068

If your program has O(n^2*log(n)) time complexity or faster try the following tests:

10
4 10
0 0
5 0
5 3
13 3
10 8
5 8
7 5
2 1
5 10

Answer:
12.276044

24
13 10
11 17
7 20
1 20
1 11
13 0
23 7
23 19
14 22
20 18
18 11
13 6
5 15
13 4
20 8
13 3
8 7
3 14
3 17
6 17
13 8
17 17
11 20
14 17

Answer:
20.645581

29
17 13
11 12
10 10
12 6
22 6
23 13
12 18
0 14
12 1
14 2
7 12
12 15
20 13
18 10
12 10
19 8
21 13
12 16
5 13
12 3
2 14
12 17
22 13
21 7
12 7
11 10
19 13
13 14
10 13

Answer:
18.193976

Edited by author 25.08.2019 17:28