n: 4 m: 4
0 [1,4][1,4][1,4]
[1,4]0 [1,4][1,4]
[1,4][1,4]0 [1,4]
[1,4][1,4][1,4]0 

n: 4 m: 4
0 [3,4][2,3][1,2]
[3,4]0 [2,3][1,2]
[2,3][2,3]0 [1,2]
[1,2][1,2][1,2]0 

(d,(c,(b,a)3)2)1;
n: 4 m: 4
0 3 2 1 
3 0 2 1 
2 2 0 1 
1 1 1 0 

[a, b, c, d]
a b c 1 (0,1,2)
b c d 1 (1,2,3)
 time: 15 nodes: 2