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QOJ
| ID | Problem | Submitter | Result | Time | Memory | Language | File size | Submit time | Judge time |
|---|---|---|---|---|---|---|---|---|---|
| #641050 | #5. 在线 O(1) 逆元 | SkyMaths | 100 ✓ | 5003ms | 394536kb | C++20 | 347b | 2024-10-14 18:05:15 | 2024-10-14 18:05:15 |
Judging History
answer
#include "inv.h"
#include<bits/stdc++.h>
using namespace std;
const int N=1e8+5,mod=998244353;
int n=N-5,I[N];
void init(int p)
{
I[1]=1;
for(int i=2;i<=n;i++) I[i]=mod-1ll*(mod/i)*I[mod%i]%mod;
}
int inv(int x)
{
if(x<=n) return I[x];int q=mod/x,r=mod%x;
if(r<x/2) return mod-1ll*q*inv(r)%mod;
return 1ll*(q+1)*inv(x-r)%mod;
}
Details
Pretests
Final Tests
Test #1:
score: 30
Accepted
time: 651ms
memory: 394532kb
Test #2:
score: 40
Accepted
time: 1099ms
memory: 394536kb
Test #3:
score: 30
Accepted
time: 5003ms
memory: 394352kb