bzoj2242 [SDOI2011]计算器

 1 #include <bits/stdc++.h>
 2 #define il inline
 3 #define RG register
 4 #define ll long long
 5 
 6 using namespace std;
 7 
 8 map <ll,ll> mp;
 9 
10 il ll gi(){
11   RG ll x=0,q=1; RG char ch=getchar();
12   while ((ch<‘0‘ || ch>‘9‘) && ch!=‘-‘) ch=getchar();
13   if (ch==‘-‘) q=-1,ch=getchar();
14   while (ch>=‘0‘ && ch<=‘9‘) x=x*10+ch-48,ch=getchar();
15   return q*x;
16 }
17 
18 il ll qpow(RG ll a,RG ll b,RG ll p){
19   RG ll ans=1;
20   while (b){
21     if (b&1) ans=ans*a%p;
22     a=a*a%p,b>>=1;
23   }
24   return ans;
25 }
26 
27 il ll exgcd(RG ll a,RG ll b,RG ll &x,RG ll &y){
28   if (!b){ x=1,y=0; return a; }
29   RG ll t=exgcd(b,a%b,y,x); y-=a/b*x; return t;
30 }
31 
32 int main(){
33 #ifndef ONLINE_JUDGE
34   freopen("calc.in","r",stdin);
35   freopen("calc.out","w",stdout);
36 #endif
37   RG ll T=gi(),k=gi();
38   if (k==1){
39     while (T--){
40       RG ll a=gi(),b=gi(),p=gi();
41       printf("%lld\n",qpow(a,b,p));
42     }
43   }
44   if (k==2){
45     while (T--){
46       RG ll a=gi(),b=gi(),p=gi(),x,y; a%=p,b%=p;
47       RG ll t=exgcd(a,p,x,y); while (x<0) x+=p;
48       if (b%t) puts("Orz, I cannot find x!");
49       else printf("%lld\n",x*(b/t)%p);
50     }
51   }
52   if (k==3){
53     while (T--){
54       RG ll a=gi(),b=gi(),p=gi(),m=ceil(sqrt(p));
55       a%=p,b%=p; if (!a && !b){ puts("1"); continue; }
56       if (!a){ puts("Orz, I cannot find x!"); continue; }
57       mp.clear(); RG ll am=qpow(a,m,p),fg=0;
58       for (RG ll i=0,t=b;i<m;++i,t=t*a%p) mp[t]=i;
59       for (RG ll i=1,x=am;i*i<=p+1;++i,x=x*am%p)
60     if (mp.count(x)){ printf("%lld\n",i*m-mp[x]),fg=1; break; }
61       if (!fg) puts("Orz, I cannot find x!");
62     }
63   }
64   return 0;
65 }