bzoj2242: [SDOI2011]计算器.

  1 #include<map>
  2 #include<cmath>
  3 #include<cstdio>
  4 using namespace std;
  5 typedef long long ll;
  6 map<int,int>mp;
  7 inline int input() {
  8     char c=getchar();int x=0,a=1;
  9     for(;c<‘0‘||c>‘9‘;c=getchar())
 10         if(c==‘-‘) a=-1;
 11     for(;c>=‘0‘&&c<=‘9‘;c=getchar())
 12         x=(x<<1)+(x<<3)+c-‘0‘;
 13     return x*a;
 14 }
 15 inline ll poowmod(ll a,int k,int p) {
 16     ll ret=1;
 17     for(;k;k>>=1,a=(a*a)%p)
 18         if(k&1) ret=(ret*a)%p;
 19     return ret;
 20 }
 21 int gcd(int a,int b) {
 22     return b==0?a:gcd(b,a%b);
 23 }
 24 void exgcd(int a,int b,int &x,int &y) {
 25     if(b==0) {
 26         x=1,y=0;
 27         return;
 28     }
 29     exgcd(b,a%b,x,y);
 30     int t=x;
 31     x=y;
 32     y=t-(a/b)*y;
 33     return ;
 34 }
 35 inline void linemod(int y,int z,int p) {
 36     int g=gcd(y,p),a,b;
 37     if(z%g){
 38         printf("Orz, I cannot find x!\n");
 39         return;
 40     }
 41     y/=g;
 42     z/=g;
 43     p/=g;
 44     exgcd(y,p,a,b);
 45     a=(ll)a*z%p;
 46     while(a<0) a+=p;
 47     printf("%d\n",a);
 48     return;
 49 }
 50 inline void bsgs(int y,int z,int p) {
 51     mp.clear();
 52     if((y%=p)==0&&z==0) {
 53         printf("1\n");
 54         return;
 55     }
 56     if(y==0) {
 57         printf("Orz, I cannot find x!\n");
 58         return;
 59     }
 60     ll m=ceil(sqrt(p+0.5));
 61     mp[1]=m+1;
 62     for(ll i=1,t=1;i<m;i++) {
 63         t=(t*y)%p;
 64         if(!mp[t]) mp[t]=i;
 65     }
 66     ll inv=1,tmp=poowmod(y,p-m-1,p);
 67     for(ll k=0;k<m;k++,inv=(inv*tmp)%p) {
 68         int i=mp[(z*inv)%p];
 69         if(i) {
 70             printf("%lld\n",k*m+(i==m+1?0:i));
 71             return;
 72         }
 73     }
 74     printf("Orz, I cannot find x!\n");
 75     return;
 76 }
 77 void solve(int T,int L) {
 78     if(L==1) {
 79         while(T--) {
 80             int y=input(),z=input(),p=input();
 81             printf("%lld\n",poowmod(y,z,p));
 82         }
 83     } else if(L==2) {
 84         while(T--) {
 85             int y=input(),z=input(),p=input();
 86             linemod(y,z,p);
 87         }
 88     } else {
 89         while(T--) {
 90             int y=input(),z=input(),p=input();
 91             bsgs(y,z,p);
 92         }
 93     }
 94     return;
 95 }
 96 int main() {
 97     int T=input(),L=input();
 98     solve(T,L);
 99     return 0;
100 }