```
for(int i=1;i<=n;++i) {
LL inv_a=ksm(a[i][i],MODD-2);
for(int j=i+1;j<=n;++j) {
if(i==j) continue;
LL rat=a[j][i]*inv_a%MODD;
a[j][i]=0;
a[j][i+1]=((a[j][i+1]-a[i][i+1]*rat%MODD)%MODD+MODD)%MODD;
a[j][n+1]=((a[j][n+1]-a[i][n+1]*rat%MODD)%MODD+MODD)%MODD;
}
}
```
就是这一坨东西里面的
by daduoli @ 2023-04-19 16:26:48
Cu ball
by 北文 @ 2023-04-19 16:29:00
悬赏 $2$ 关注
by daduoli @ 2023-04-19 16:36:26
@[Cust10](/user/307535)
by daduoli @ 2023-04-19 16:39:42
@[MCCF](/user/62440)
by daduoli @ 2023-04-19 16:39:56
没事了
```
for(int j=1;j<=n;++j) {
if(i==j) continue;
LL rat=a[j][i]*inv_a%MODD;
a[j][i]=0;
if(i<n) a[j][i+1]=((a[j][i+1]-a[i][i+1]*rat%MODD)%MODD+MODD)%MODD;
a[j][n+1]=((a[j][n+1]-a[i][n+1]*rat%MODD)%MODD+MODD)%MODD;
}
```
要加个特判
by daduoli @ 2023-04-19 18:24:53