高精度大数运算模板

来源：互联网发布：cs结构的java开发编辑：程序博客网时间：2024/05/22 00:28
#define MAX 100000  #define base 10000  #define digit 4    struct bigint  {      int c[MAX];      int len;      void init()      {          len = 0;          memset(c,0,sizeof(c));      }        bigint()      {          init();          len = 1;      }        bigint(int n)      {          init();          do {              c[len++] = n%base;              n /= base;          } while(n);      }        bigint(char* s)      {          init();          for(int i=strlen(s);i>=0;i--)              c[i/4] = c[i/4]*10 + c[i] - '0';      }        bigint(const bigint & n)      {          *this = n;      }        bigint & operator = (const bigint & a)      {          len = a.len;          for(int i=0;i<len;i++) c[i] = a.c[i];          return *this;      }        bigint operator + (const bigint & a) const      {          bigint t;          t.len = max(a.len,len);          for(int i=0;i<t.len;i++)              t.c[i] = c[i]+a.c[i];          for(int i=0;i<t.len;i++)              t.c[i+1] += t.c[i]/base, t.c[i] %= base;          if(t.c[t.len]) t.len++;          return t;      }        bigint operator * (const bigint & a) const      {          bigint t;          t.len = a.len+len+2;          for(int i=0;i<len;i++) for(int j=0;j<a.len;j++)          {              t.c[i+j] += c[i]*a.c[j];              t.c[i+j+1] += t.c[i]/base;              t.c[i+j] %= base;          }          for(int i=0;i<t.len;i++)          {              t.c[i+1] += t.c[i]/base;              t.c[i] %= base;          }          while(!t.c[t.len-1]) t.len--;          return t;      }        void out()      {          printf("%d",c[len-1]);          for(int i=len-2;i>=0;i--)          {              printf("%04d",c[i]);          }      }        friend ostream & operator << (ostream & os,const bigint & a)      {          os << a.c[a.len - 1];          for(int i = a.len - 2;i>=0;i--)          {              os.width(digit);              os.fill('0');              os << a.c[i];          }          return os;      }        friend istream & operator >> (istream & is,bigint & a)      {          char s[MAX*4+1];          is>>s;          bigint t(s);          a = t;          return is;      }  };
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