明白了 ```c++ if (l.op and l.lc == l.ln) { x.lc = l.ln + r.lc; x.lm = 1ll * l.lm * r.lm; } if (l.op and r.rc == r.ln) { x.rc = r.ln + l.rc; x.rm = 1ll * r.rm * l.rm; } ``` 这两句没取模。 by AtomAlpaca @ 2023-08-22 17:02:36