很玄学,我用高精暴力对指数取模k mod 998244353k\bmod998244353kmod998244353,然后跑快速幂,结果ACACAC了,但让指数kkk对φ(998244353)\varphi(998244353)φ(998244353)即(998244352)(998244352)(998244352)取模后再加上(998244352)(998244352)(998244352)却WrongWrongWrong掉了。
k%=Mod; k%=phi; k+=phi;