First I used Kruskal algo but got WA9 verdict.
My program didn't give right answer for next test:
4 1
4
0    1    1    100000
1    0    1    100000
1    1    0    100000
100000    100000    100000    0
right answer:
100002

Implementation of Prim algo gave the correct answer at last.

HM, i have right output on this test, but  WA 9

c[i][j] = c[j][i]
This is wrong test

This test helped me....

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

=8

(I was getting 9).  Basically my algorithm (roughly Prim's) tried to short-cut checking vertex weights.  For any node, make sure you check verices to ALL nodes....

Some tests:
4 2
1 4
0 4 8 9
4 0 2 7
8 2 0 1
9 7 1 0
Answer 3

4 2
1 3
0 6 7 8
6 0 2 3
7 2 0 4
8 3 4 0
Answer 5

Edited by author 27.10.2015 20:10

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

answer is 7

Edited by author 19.02.2019 12:09

One more test that helped me to find my error for WA #9.

5 2
1 5
0 1 100 150 200
1 0 10 50 200
100 10 0 11 100
150 50 11 0 2
200 200 100 2 0

Answer: 13