本道题我没打出来，因为c++字符串处理不会用，后来托这个网站的福，打出来了，用了高精度类，300多行，应该是我打过最长的代码了吧。
1 #include<bits/stdc++.h>
2 using namespace std;
3 class Int{
4 #define BASE 1000000000
5 public:
6 typedef long long value;
7 void New(size_t l){
8 if (a!=NULL)delete[] a;a=new value[l];
9 len=1;a[0]=0;sign=1;
10 }
11 Int():a(NULL),base(BASE){New(1);}
12 Int(value x):a(NULL),base(BASE){New(1);*this=x;}
13 Int(value x,value _base):a(NULL),base(_base){New(1);*this=x;}
14 Int(const Int &B):a(NULL),base(BASE){New(1);*this=B;}
15 ~Int(){delete[] a;}
16 Int& operator =(value x){
17 size_t l=1;for (value x1=max(x,-x);x1>=base;++l,x1/=base);New(l);
18 if (x<0)x=-x,sign=0;else sign=1;
19 len=0;while (x)a[len++]=x%base,x/=base;
20 if (!len)a[len++]=0;
21 return *this;
22 }
23 Int& operator =(const Int &A){
24 New(A.len);len=A.len;memcpy(a,A.a,sizeof(value)*len);
25 base=A.base;sign=A.sign;return *this;
26 }
27 friend Int operator -(Int A){A.sign=1-A.sign;return A;}
28 bool operator !(){if (len==1&&a[0]==0)return 1;else return 0;}
29 friend Int operator +(Int A,Int B){
30 if (A.sign!=B.sign){B.sign=1-B.sign;return A-B;}
31 if (A.base!=B.base)
32 if (A.base>B.base)B.set_base(A.base);
33 else A.set_base(B.base);
34 Int res;res.set_base(A.base); int len=A.len>B.len?A.len:B.len;
35 res.New(len+1);res.sign=A.sign;
36 memset(res.a,0,(len+1)*sizeof(value));
37 for (int i=0;i<len;++i){
38 if (i<A.len)res.a[i]+=A.a[i];
39 if (i<B.len)res.a[i]+=B.a[i];
40 }
41 for (int i=0;i<len;++i)
42 if (res.a[i]>=res.base)++res.a[i+1],res.a[i]-=res.base;
43 if (res.a[len])res.len=len+1;else res.len=len;
44 if (!res)res.sign=1;return res;
45 }
46 friend Int operator -(Int A,Int B){
47 if (A.sign!=B.sign){B.sign=1-B.sign;return A+B;}
48 if (A.base!=B.base)
49 if (A.base>B.base)B.set_base(A.base);
50 else A.set_base(B.base);
51 if (small(A,B))swap(A,B),A.sign=1-A.sign;
52 Int res;res.set_base(A.base); int len=A.len>B.len?A.len:B.len;
53 res.New(len);res.sign=A.sign;
54 memset(res.a,0,len*sizeof(value));
55 for (int i=0;i<len;++i){
56 if (i>=B.len)res.a[i]+=A.a[i];
57 else res.a[i]+=A.a[i]-B.a[i];
58 if (res.a[i]<0)res.a[i]+=res.base,--res.a[i+1];
59 }
60 while (len>1&&!res.a[len-1])--len;res.len=len;
61 if (!res)res.sign=1;return res;
62 }
63 friend Int operator *(Int A,Int B){
64 if (A.base!=B.base)
65 if (A.base>B.base)B.set_base(A.base);
66 else A.set_base(B.base);
67 Int res;res.set_base(A.base); int len=A.len+B.len;
68 res.New(len);res.sign=(A.sign==B.sign);
69 memset(res.a,0,len*sizeof(value));
70 for (int i=0;i<A.len;++i)
71 for (int j=0;j<B.len;++j){
72 res.a[i+j]+=A.a[i]*B.a[j];
73 res.a[i+j+1]+=res.a[i+j]/res.base;
74 res.a[i+j]%=res.base;
75 }
76 /*
77 for (int i=0;i<A.len;++i)
78 for (int j=0;j<B.len;++j)res.a[i+j]+=A.a[i]*B.a[j];
79 for (int i=0;i<len-1;++i)res.a[i+1]+=res.a[i]/res.base,res.a[i]%=res.base;
80 */
81 while (len>1&&!res.a[len-1])--len;res.len=len;
82 return res;
83 }
84 friend pair<Int,Int> divide(Int A,Int B){
85 if (!B){puts("error:div zero!");for (;;);}
86 if (A.base!=B.base)
87 if (A.base>B.base)B.set_base(A.base);
88 else A.set_base(B.base);
89 if (small(A,B))return make_pair(Int(0),A);
90 Int C,D;C.set_base(A.base);D.set_base(A.base);C.New(A.len);C.len=A.len;
91 bool Csign=(A.sign==B.sign),Dsign=A.sign;A.sign=B.sign=1;
92 for (int i=A.len-1;i>=0;--i){
93 C.a[i]=0;D=D*D.base;D.a[0]=A.a[i];
94 int l=0,r=A.base-1,mid;
95 while (l<r){
96 mid=(l+r+1)>>1;
97 if (small(B*mid,D+1))l=mid;
98 else r=mid-1;
99 }
100 C.a[i]=l;D=D-B*l;
101 }
102 C.sign=Csign;D.sign=Dsign;if (!D)D.sign=1;
103 while (C.len>1&&!C.a[C.len-1])--C.len;
104 return make_pair(C,D);
105 }
106 Int operator /(value x){
107 if (!x){puts("error:div zero!");for (;;);}
108 value d=0;Int res;res.set_base(base);res.New(len);res.len=len;
109 if (x<0)x=-x,res.sign=(sign==0);
110 else res.sign=(sign==1);
111 for (int i=len-1;i>=0;--i)
112 d=d*base+a[i],res.a[i]=d/x,d%=x;
113 while (res.len>1&&!res.a[res.len-1])--res.len;
114 return res;
115 }
116 Int operator %(value x){
117 value d=0;if (x<0)x=-x;
118 for (int i=len-1;i>=0;--i)d=(d*base+a[i])%x;
119 return d;
120 }
121 friend Int abs(Int A){A.sign=1;return A;}
122 friend bool small(Int A,Int B){
123 if (A.base!=B.base)
124 if (A.base>B.base)B.set_base(A.base);
125 else A.set_base(B.base);
126 if (A.len!=B.len)return A.len<B.len;
127 for (int i=A.len-1;i>=0;--i)
128 if (A.a[i]!=B.a[i])return A.a[i]<B.a[i];
129 return 0;
130 }
131 friend bool operator <(Int A,Int B){
132 if (A.sign!=B.sign)return A.sign<B.sign;
133 return A.sign==1?small(A,B):small(B,A);
134 }
135 friend bool operator ==(Int A,Int B){
136 if (A.base!=B.base)
137 if (A.base>B.base)B.set_base(A.base);
138 else A.set_base(B.base);
139 if (A.sign!=B.sign||A.len!=B.len)return 0;
140 for (int i=0;i<A.len;++i)if (A.a[i]!=B.a[i])return 0;
141 return 1;
142 }
143 friend bool operator !=(Int A,Int B){return !(A==B);}
144 friend bool operator >(Int A,Int B){return !(A<B||A==B);}
145 friend bool operator <=(Int A,Int B){return A<B||A==B;}
146 friend bool operator >=(Int A,Int B){return A>B||A==B;}
147 Int operator /(Int B){return divide(*this,B).first;}
148 Int operator %(Int B){return divide(*this,B).second;}
149 Int& operator +=(Int B){*this=*this+B;return *this;}
150 Int& operator -=(Int B){*this=*this-B;return *this;}
151 Int& operator *=(Int B){*this=*this*B;return *this;}
152 Int& operator /=(Int B){*this=*this/B;return *this;}
153 Int& operator %=(Int B){*this=*this%B;return *this;}
154 Int& operator ++(){*this=*this+1;return *this;}
155 Int& operator --(){*this=*this-1;return *this;}
156 Int operator ++(int){Int res(*this);*this=*this+1;return res;}
157 Int operator --(int){Int res(*this);*this=*this-1;return res;}
158 Int operator +(value x){return *this+Int(x,this->base);}
159 Int operator -(value x){return *this-Int(x,this->base);}
160 Int operator *(value x){return *this*Int(x,this->base);}
161 //Int operator /(value x){Int T;T=x;return *this/T;}
162 //Int operator %(value x){Int T;T=x;return *this%T;}
163 Int& operator *=(value x){*this=*this*x;return *this;}
164 Int& operator +=(value x){*this=*this+x;return *this;}
165 Int& operator -=(value x){*this=*this-x;return *this;}
166 Int& operator /=(value x){*this=*this/x;return *this;}
167 Int& operator %=(value x){*this=*this%x;return *this;}
168 bool operator ==(value x){return *this==Int(x,this->base);}
169 bool operator !=(value x){return *this!=Int(x,this->base);}
170 bool operator <=(value x){return *this<=Int(x,this->base);}
171 bool operator >=(value x){return *this>=Int(x,this->base);}
172 bool operator <(value x){return *this<Int(x,this->base);}
173 bool operator >(value x){return *this>Int(x,this->base);}
174 friend Int gcd(Int x,Int y){
175 Int t;int cnt=0;
176 while (1){
177 if (x<y)t=x,x=y,y=t;
178 if (y==0){
179 while (cnt--)x*=2;
180 return x;
181 }
182 if (x%2==0&&y%2==0)x/=2,y/=2,++cnt;
183 else if (x%2==0)x/=2;
184 else if (y%2==0)y/=2;
185 else {t=x;x=y;y=t-y;}
186 }
187 }
188 void to_arr(char *c){
189 char *c1=c;
190 for (int i=0;i<len-1;++i)
191 for (value x=a[i],b=base/10;b>=1;b/=10)*c1++=‘0‘+x%10,x/=10;
192 for (value x=a[len-1];x>0;x/=10)*c1++=‘0‘+x%10;
193 if (len==1&&a[len]==0)*c1++=‘0‘;
194 if (sign==0)*c1++=‘-‘;*c1=0;reverse(c,c1);
195 }
196 void from_arr(char *c){
197 size_t base_l=get_basel(),b=1;int cl=strlen(c);value x=0;
198 New((cl+base_l-1)/base_l);len=0;
199 if (*c==‘-‘)sign=0,++c,--cl;else sign=1;
200 while (--cl>=0){
201 x+=(c[cl]-‘0‘)*b;b*=10;if (b==base)a[len++]=x,x=0,b=1;
202 }
203 if (!len||x)a[len++]=x;
204 while (len>1&&!a[len-1])--len;
205 }
206 void set_base(int _base){
207 if (base==_base)return;
208 char *c=new char[len*get_basel()+1];
209 to_arr(c);base=_base;from_arr(c);
210 delete[] c;
211 }
212 void set_basel(int _l){
213 size_t _base=1;while (_l--)_base*=10;set_base(_base);
214 }
215 void read(){
216 vector<char> s;char ch;
217 scanf(" %c",&ch);if (ch==‘-‘)s.push_back(‘-‘),ch=getchar();
218 for (;ch>=‘0‘&&ch<=‘9‘;ch=getchar())s.push_back(ch);
219 char *c=new char[s.size()+1];
220 for (int i=0;i<s.size();++i)c[i]=s[i];c[s.size()]=0;
221 from_arr(c);delete[] c;
222 if (!*this)this->sign=1;
223 }
224 void print(){
225 if (!sign)putchar(‘-‘);
226 printf("%d",int(a[len-1]));
227 for (int i=len-2;i>=0;--i){
228 for (int j=base/10;j>=10;j/=10)
229 if (a[i]<j)putchar(‘0‘);
230 else break;
231 printf("%d",(int)a[i]);
232 }
233 }
234 string inttostring(int x){
235 stringstream a;
236 a<<x;
237 string b;
238 a>>b;
239 return b;
240 }
241 string prin(){
242 string ss="";
243 if (!sign) ss+=‘-‘;
244 ss+=inttostring(a[len-1]);
245 for (int i=len-2;i>=0;--i){
246 for (int j=base/10;j>=10;j/=10)
247 if (a[i]<j) ss+=‘0‘;
248 else break;
249 ss+=inttostring(a[i]);
250 }
251 return ss;
252 }
253 void println(){print();putchar(‘\n‘);}
254 private:
255 value *a,base;int len;bool sign; //0="-"
256 size_t get_basel()const
257 {
258 size_t res=0;for (int b=base/10;b>=1;b/=10,++res);
259 return res;
260 }
261 #undef BASE
262 };//高精类
263 string s,ans;
264 Int a,c=1,ll=1,l=1;
265 int b,k,ppop[3010];
266 int main(){
267 freopen("exp.in","r",stdin);
268 freopen("exp.out","w",stdout);
269 cin>>s;
270 cin>>b;
271 int tp=0;int len=s.size();int lls;
272 for(int i=0;i<len;i++){
273 if(s[i]==‘.‘) lls=i;
274 }
275 for(int i=lls+1;i<len;i++){
276 ppop[tp++]=s[i];
277 }
278 tp--;
279 while(ppop[tp]==‘0‘) tp--;
280 k=s.length();
281 while(s[k-1]==‘0‘){s.erase(k-1,1);k--;}
282 if (s[0]==‘.‘) s=‘0‘+s;
283 for (int i=0;i<s.length();i++)
284 {
285 if (s[i]==‘.‘) l*=10;
286 else if (l>=10) a=a*10+s[i]-‘0‘;else a=a*10+s[i]-‘0‘,l*=10;
287 }
288 for (int i=1;i<=b;i++) c=c*a,ll=ll*l;//c为去小数点的数，l为小数点pow(10,位数),c/l为answer,但有精度问题。
289 string qwq;
290 qwq=c.prin();
291 string pwp;
292 pwp=ll.prin();
293 int us=(tp+1)*b;
294 us=qwq.size()-us;//找小数点位数
295 bool bi=0;
296 // us--;
297 if (us<0) putchar(‘.‘),bi=1;
298 while(us<0)
299 {
300 putchar(‘0‘);
301 us++;
302 }
303 for(int i=0;i<qwq.size();i++)
304 {
305 if(i==us&&bi==0) putchar(‘.‘);//到小数点输出小数点,否则输出数字
306 putchar(qwq[i]);
307 }
308 return 0;
309 }
原文地址：https://www.cnblogs.com/GREED-VI/p/9537234.html
时间： 2024-11-09 01:58:17