B-M算法求已知序列极小多项式

B-M算法求已知序列极小多项式

算法代码(c++)

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>
#include<iostream>
using namespace std;
int B_M(int a[],int nn);
int cc[20000]={0},dd[20000]={0},ss[20000]={0},l[20000]={0},ee[20000]={0},b[20000];
int main()
{
    int nn=0,v=0;
    char line[20000];
    cout<<"请输入序列a:";//直接输入01比特串,不用打空格
    cin>>line;
    nn=strlen(line);
    for(v=0;v<nn;v++)
    {
        b[v]=line[v]-48;
    }

    B_M(b,nn);
    system("pause");
    return 0;
}

int B_M(int a[],int nn)
{

    int i=0,j=0,k=0,e=0,t=0;
    int m=0,d1=0;
    for(i=0;i<nn;i++)//初始化
        if(a[i]==1)//判断第i位是0还是1,1进入语句,0则跳过//
        {
            e=i;//记录第一个1的位置
            l[i]=e+1;//记录有1的地方,记为i+1,作为线性复杂度
            cc[0]=1;
            for(j=1;j<=e;j++)
            {
                cc[j]=0;
            }
            cc[e+1]=1;
            break;//遇到第一个1便终止//
        }
        else
        {
            cc[i]=0;
            l[i]=0;
        }
    dd[0]=1;
    for(i=1;i<2000;i++)
    {
        dd[i]=0;
    }
    for(i=e+1;i<nn;i++)
    {
        d1=a[i];
        for(j=0;j<l[i-1];j++)
           {d1=d1^(cc[j]&(a[j+i-l[i-1]]));}
        if(d1==0)//判断是否零化下一个比特
        {
            l[i]=l[i-1];
        }
        else//不能零化
        {
            j=i-1;
           do
           {
               j=j-1;
           }
           while(l[j]==l[j+1]);
           m=j+1;
           k=abs(m-l[m-1]-(i-l[i-1]));//计算线性复杂度跳跃点和k值

            if((m-l[m-1])>=(i-l[i-1]))
            {
                for(j=0;j<k;j++)
                {
                    ee[j]=cc[j];
                }
                for(j=k;j<=l[i-1];j++)
                {
                    ee[j]=(cc[j])^(dd[j-k]);
                }
                for(j=0;j<=1999;j++)
                {
                    cc[j]=ee[j];
                }
                l[i]=l[i-1];

            }
            else
            {
                for(j=0;j<2000;j++)
                {
                    ss[j]=cc[j];
                }
                for(j=0;j<k;j++)
                {
                    ee[j]=dd[j];
                }

                for(j=k;j<=(k+l[i-1]);j++)
                {
                    ee[j]=(dd[j])^(cc[j-k]);
                }
                for(j=0;j<=1999;j++)
                {
                    cc[j]=ee[j];
                }
                l[i]=k+l[i-1];
                for(j=0;j<2000;j++)//记录跳跃前的多项式系数
                {
                    dd[j]=ss[j];
                }
            }
        }
    }
    for(i=0;i<=nn;i++)
    {
        if(cc[i]==1)
        {
        t=i;
        break;
        }
    }
    cout<<"序列a("<<nn<<")=(";
    for(i=0;i<nn;i++)
        cout<<a[i];
    cout<<")的极小多项式为:"<<endl;
    if(t==0)
    {
    cout<<"f(x)=";
    for(i=l[nn-1];i>0;i--)
       {
        if(cc[i]==1)
            {cout<<"x^"<<i<<"+";}
        else
            continue;
       }
    cout<<"1";
    }
    else
    {
        cout<<"f(x)=";
        for(j=l[nn-1];j>t;j--)
        {
            if(cc[j]==1)
                cout<<"x^"<<j<<"+";
            else
                continue;
        }
        cout<<"x^"<<t;
    }
    cout<<endl;
    cout<<"dn="<<d1<<endl;
    cout<<"m="<<m<<endl;
    cout<<"k="<<k<<endl;
    cout<<"线性复杂度为:"<<endl;
    cout<<"l="<<l[nn-1]<<endl;
    cout<<"极小多项式系数为";
    for(i=l[nn-1];i>=0;i--)
        cout<<cc[i];
       cout<<endl;
}

可以处理无限数据,其线性复杂度 //by史瑞 //LFSR线性移位寄存器以及异或运算OK unsigned char LFSRB_M(unsigned char *fun,unsigned char *seq,unsigned long Cont){ unsigned long x; unsigned char ch=0x00,t=0x00,*array; array=(unsigned char *)malloc(Cont*sizeof(unsigned char)); for(x=0;x<Cont;x++) *(array+x)=(*(seq+x))&(*(fun+x)); for(x=0;x<Cont*8;x++){ ch=(*array)&0x80; LeftShift(array,Cont); t^=ch; } free(array); return t; } #define word(ln) ((ln-1)/8+1) #define place(ln) ((ln-1)%8) //Berlek_Massey生成任意序列的联接多项式OK unsigned char *Berlek_Massey(unsigned char *seq,unsigned long *Rank,unsigned long Cont,FILE *fmm){ unsigned long n=0,m,lm,ln=0; int d; unsigned long lfm; unsigned char *fun,*fm,*array,ch,t=0x00; unsigned char *func,*fmc; unsigned long x,y,k; fun=(unsigned char *)malloc(sizeof(unsigned char)); *(fun)=0x00; for(x=0;x<Cont*8;x++){ if(ln!=0){ array=(unsigned char *)malloc(word(ln)); InitialDSR(array,word(ln)); for(y=0;y<ln;y++){ ch=((*(seq+(n-(y+1))/8))<<((n-(y+1))%8))&0x80; if(ch) *(array+y/8)^=(ch>>(y%8)); } t=LFSRB_M(fun,array,word(ln)); d=((((*(seq+n/8))<<(n%8))&0x80;)^t)?1:0; free(array); } else d=(((*(seq+n/8))<<(n%8))&0x80;)?1:0; if(d){ if(ln!=0){ lm=ln; func=(unsigned char *)malloc(word(ln)*sizeof(unsigned char)); memcpy(func,fun,word(ln)); if(ln<(n+1-ln)){ ln=n+1-ln; } fmc=(unsigned char *)malloc(word(ln)*sizeof(unsigned char)); InitialDSR(fmc,word(ln)); memcpy(fmc,fm,word(lfm)); for(k=0;k<n-m;k++){ RightShift(fmc,word(ln)); } ch=0x80; *(fmc+(n-m-1)/8)^=(ch>>((n-m-1)%8)); fun=(unsigned char *)realloc(fun,word(ln)*sizeof(unsigned char)); for(k=word(lm);k<word(ln);k++) *(fun+k)=0x00; XorDSR(fun,fmc,word(ln)); free(fmc); if(lm<(n+1-lm)){ m=n; lfm=lm; fm=(unsigned char *)realloc(fm,word(lm)); memcpy(fm,func,word(lfm)); } free(func); } else{ ln=n+1; m=n; if(m!=0){ fm=(unsigned char *)malloc(word(m)*sizeof(unsigned char)); InitialDSR(fm,word(m)); lfm=m; } else{ fm=(unsigned char *)malloc(sizeof(unsigned char)); *fm=0x00; lfm=1; } fun=(unsigned char *)realloc(fun,word(ln)); InitialDSR(fun,word(ln)); ch=0x80; ch>>=(place(ln)); *(fun+(word(ln)-1))^=ch; } } n++; printf("\t<%d,%d>",n,ln); fprintf(fmm,"\t<n,d,ln>=<%d,%d,%d>",n,d,ln); if(n%3==0){ printf("\n"); fprintf(fmm,"\n"); } } printf("\nFn="); // for(k=0;k<word(ln);k++) // FromBytetoBit(*(fun+k)); *Rank=ln; return fun; }
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