大整数类（模板）

转载

mob604756ebc436 2018-09-13 16:51:00

  1 /*支持加减乘除、取模、赋值、输入输出*/
  2 const int MAX_SIZE = 5000 + 10;  //最大位数
  3 
  4 struct BigInteger
  5 {
  6     int len, s[MAX_SIZE];
  7     BigInteger()
  8     {
  9         memset(s, 0, sizeof(s));
 10         len = 1;
 11     }
 12     BigInteger(int num) { *this = num; }
 13     BigInteger(const char *num) { *this = num; }
 14     void clean() { while (len > 1 && !s[len - 1])len--; }
 15     BigInteger operator = (const int num)
 16     {
 17         char s[MAX_SIZE];
 18         sprintf(s, "%d", num);
 19         *this = s;
 20         return *this;
 21     }
 22     BigInteger operator = (const char *num)
 23     {
 24         len = strlen(num);
 25         for (int i = 0; i < len; i++)s[i] = num[len - i - 1] - '0';
 26         return *this;
 27     }
 28     BigInteger operator + (const BigInteger& b)
 29     {
 30         BigInteger c;
 31         c.len = 0;
 32         for (int i = 0, g = 0; g || i < max(len, b.len); i++)
 33         {
 34             int x = g;
 35             if (i < b.len)x += b.s[i];
 36             if (i < len)x += s[i];
 37             c.s[c.len++] = x % 10;
 38             g = x / 10;
 39         }
 40         return c;
 41     }
 42     BigInteger operator - (const BigInteger& b)
 43     {
 44         BigInteger c;
 45         c.len = 0;
 46         for (int i = 0, g = 0; i < len; i++)
 47         {
 48             int x = s[i] - g;
 49             if (i < b.len)x -= b.s[i];
 50             if (x >= 0)g = 0;
 51             else { g = 1; x += 10; }
 52             c.s[c.len++] = x;
 53         }
 54         c.clean();
 55         return c;
 56     }
 57     BigInteger operator * (const BigInteger& b)
 58     {
 59         BigInteger c;
 60         c.len = len + b.len;
 61         for (int i = 0; i < len; i++)
 62         {
 63             for (int j = 0; j < b.len; j++)
 64             {
 65                 c.s[i + j] += s[i] * b.s[j];
 66             }
 67         }
 68         for (int i = 0; i < c.len; i++)
 69         {
 70             c.s[i + 1] += c.s[i] / 10;
 71             c.s[i] %= 10;
 72         }
 73         c.clean();
 74         return c;
 75     }
 76     BigInteger operator * (const int& b)
 77     {
 78         BigInteger c;
 79         c.len = 0;
 80         for (int i = 0, g = 0; g || i < len; i++)
 81         {
 82             int x;
 83             if (i < len)x = s[i] * b + g;
 84             else x = g;
 85             c.s[c.len++] = x % 10;
 86             g = x / 10;
 87         }
 88         return c;
 89     }
 90     BigInteger operator / (const BigInteger& b)
 91     {
 92         BigInteger c, f = 0;
 93         for (int i = len - 1; i >= 0; i--)
 94         {
 95             f = f * 10;
 96             f.s[0] = s[i];
 97             while (f >= b)
 98             {
 99                 f = f - b;
100                 c.s[i]++;
101             }
102         }
103         c.len = len;
104         c.clean();
105         return c;
106     }
107     BigInteger operator / (const int& b)
108     {
109         BigInteger c, d = *this;
110         c.len = len;
111         for (int i = len - 1, g = 0; i >= 0; i--)
112         {
113             d.s[i] += g * 10;
114             c.s[i] = d.s[i] / b;
115             g = d.s[i] % b;
116         }
117         c.clean();
118         return c;
119     }
120     BigInteger operator % (const BigInteger& b)
121     {
122         BigInteger c = *this / b;
123         c = *this - c * b;
124         return c;
125     }
126     BigInteger operator += (const BigInteger& b)
127     {
128         *this = *this + b; return *this;
129     }
130     BigInteger operator -= (const BigInteger& b)
131     {
132         *this = *this - b; return *this;
133     }
134     BigInteger operator *= (const BigInteger& b)
135     {
136         *this = *this*b; return *this;
137     }
138     BigInteger operator /= (const BigInteger& b)
139     {
140         *this = *this / b; return *this;
141     }
142     BigInteger operator *= (const int& b)
143     {
144         *this = *this*b; return *this;
145     }
146     BigInteger operator /= (const int& b)
147     {
148         *this = *this / b; return *this;
149     }
150     BigInteger operator %= (const BigInteger& b)
151     {
152         *this = *this%b; return *this;
153     }
154     bool operator < (const BigInteger& b)
155     {
156         if (b.len != len)return len < b.len;
157         for (int i = len - 1; i >= 0; i--)
158         {
159             if (s[i] != b.s[i])return s[i] < b.s[i];
160         }
161         return 0;
162     }
163     bool operator > (const BigInteger& b)
164     {
165         if (b.len != len)return len > b.len;
166         for (int i = len - 1; i >= 0; i--)
167         {
168             if (s[i] != b.s[i])return s[i] > b.s[i];
169         }
170         return 0;
171     }
172     bool operator == (const BigInteger& b)
173     {
174         return !(*this > b) && !(*this < b);
175     }
176     bool operator <= (const BigInteger& b)
177     {
178         return !(*this > b);
179     }
180     bool operator >= (const BigInteger& b)
181     {
182         return !(*this < b);
183     }
184     bool operator != (const BigInteger& b)
185     {
186         return !(*this == b);
187     }
188     string str() const
189     {
190         string res;
191         for (int i = 0; i < len; i++)
192             res = char(s[i] + '0') + res;
193         return res;
194     }
195 };
196 istream& operator >> (istream&in, BigInteger &x)
197 {
198     string s;
199     in >> s;
200     x = s.c_str();
201     return in;
202 }
203 ostream& operator << (ostream&out, BigInteger x)
204 {
205     out << x.str();
206     return out;
207 }