原始陣列
15 0 0 22 0 -15
0 11 3 0 0 0
0 0 0 -6 0 0
0 0 0 0 0 0 0
91 0 0 0 0 0
0 0 28 0 0 0
壓縮後的陣列
6 6 8
0 0 15
0 3 22
0 5 -15
1 1 11
1 2 3
2 3 -6
4 0 91
5 2 28