I try heap and sort to get AC using java, but memory usage is about 7M.
I browse the java submits, and find some top-rank solution only using about 3M memory.
e.g.
commit 9822957 by @hduads2022_20321226, 0.14 secs, 2908 KB.
commit 9290600 by @Mikhail, 0.109 secs, 1 272 KB.
how to lower the memory usage.