ACM Exponentiation resolution
Exponentiation (POJ1001 )
Time Limit: 500MS
Memory Limit: 10000K
Description
Problems involving the computation of exact values of very large magnitude and precision are common. For example, the computation of the national debt is a taxing experience for many computer systems.
This problem requires that you write a program to compute the exact value of Rn where R is a real number ( 0.0 < R < 99.999 ) and n is an integer such that 0 < n <= 25.
Input
The input will consist of a set of pairs of values for R and n. The R value will occupy columns 1 through 6, and the n value will be in columns 8 and 9.
Output
The output will consist of one line for each line of input giving the exact value of R^n. Leading zeros should be suppressed in the output. Insignificant trailing zeros must not be printed. Don't print the decimal point if the result is an integer.
Sample Input
95.123 12
0.4321 20
5.1234 15
6.7592 9
98.999 10
1.0100 12
Sample Output
548815620517731830194541.899025343415715973535967221869852721
.00000005148554641076956121994511276767154838481760200726351203835429763013462401
43992025569.928573701266488041146654993318703707511666295476720493953024
29448126.764121021618164430206909037173276672
90429072743629540498.107596019456651774561044010001
1.126825030131969720661201
Hint
If you don't know how to determine wheather encounted the end of input:
s is a string and n is an integer
C++
while(cin>>s>>n)
{
...
}
c
while(scanf("%s%d",s,&n)==2) //to see if the scanf read in as many items as you want
/*while(scanf(%s%d",s,&n)!=EOF) //this also work */
{
...
}
Resolution
2 #include<stdio.h>
3 #include<string.h>
4
5 #define MaxLength 128
6
7 typedef struct{
8 char value[MaxLength];
9 int pos;
10 }High_Accuracy_Data;
11
12 int numlength(High_Accuracy_Data *n)
13 {
14 for (int i=0;i<MaxLength;i++)
15 {
16 if (n->value[i]==-1)
17 return i;
18 }
19 return 0;
20 }
21
22 void MultipTwo(High_Accuracy_Data *OUTData, High_Accuracy_Data INData)
23 {
24 int i=0,j=0;
25 int nlengthOUT=numlength(OUTData);
26 int nlengthIN=numlength(&INData);
27 High_Accuracy_Data c;
28
29 //Clear the buffer
30 c.pos=0;
31 for (i=0;i<MaxLength;i++)
32 {
33 c.value[i]=0;
34 }
35
36 //Caculate the two number multiplication
37 for(i=0;i<nlengthIN;i++)
38 {
39 for(j=0;j<nlengthOUT;j++)
40 {
41 c.value[i+j]+=(OUTData->value[j])*(INData.value[i]);
42
43 //eg..9*9 = 81
44 //Get the High char 8
45 c.value[i+j+1]+=c.value[i+j]/10;
46
47 //Get the low char 1
48 c.value[i+j]%=10;
49 }
50 }
51
52 for (i=nlengthOUT+nlengthIN;;i--)
53 {
54 if (c.value[i-1]!=0)
55 {
56 c.value[i]=-1;
57 break;
58 }
59 }
60
61 //Caculate the point
62 c.pos=OUTData->pos+INData.pos;
63 OUTData->pos=c.pos;
64
65 //Output
66 for (i=0;c.value[i]!=-1;i++)
67 {
68 OUTData->value[i]=c.value[i];
69 }
70 OUTData->value[i]=c.value[i];
71 }
72
73 High_Accuracy_Data *createRBuffer(char* RBuffer)
74 {
75 High_Accuracy_Data *pData=(High_Accuracy_Data *)malloc(sizeof(High_Accuracy_Data));
76
77 int len=strlen(RBuffer);
78 int i=0;
79 int bContainPoint = 0;
80
81 //clear the buffer
82 pData->pos=0;
83 for (i=0;i<MaxLength;i++)
84 {
85 pData->value[i]=0;
86 }
87
88 for (i=len-1;i>=0;i--)
89 {
90 if (RBuffer[i]=='.')
91 {
92 bContainPoint=1;
93 pData->pos=len-i-1;
94 }else
95 {
96 pData->value[len-i-1-bContainPoint]=RBuffer[i]-'0';
97 }
98 }
99 for (i=len-bContainPoint;i>=0;i--)
100 {
101 if (pData->value[i-1]!=0)
102 {
103 pData->value[i]=-1;
104 break;
105 }
106 }
107 return pData;
108 }
109
110 void printnum(High_Accuracy_Data n)
111 {
112 int len=numlength(&n);
113 int i,end=0,b=0;
114 if (n.pos>=len){
115 printf(".");
116 for (i=n.pos-len;i>0;i--)
117 printf("0");
118 }
119 if (n.pos!=0){
120 for (i=0;i<n.pos;i++)
121 if (n.value[i]!=0) {
122 end=i;
123 b=1;
124 break;
125 }
126 if (end==0&&b==0) end=n.pos;
127 }
128 for (i=len-1;i>=end;i--){
129 printf("%d",n.value[i]);
130 if (i==n.pos&&i!=end) printf(".");
131 }
132 printf("\n");
133 }
134
135 int main()
136 {
137 //base-number
138 char RBuffer[7];
139 //exponential
140 int exp;
141 //return value for the high accuracy data
142 High_Accuracy_Data *InputData=NULL,*OutPutData=NULL;
143
144 while(scanf("%s%d",RBuffer,&exp)!=EOF)
145 {
146 //95.123 12 is input value format,
147 //the last place put a '\0', no matter what the
148 //input is.
149 RBuffer[6]='\0';
150
151 //Clean the buffer
152 if (InputData!=NULL) free(InputData);
153 if (OutPutData!=NULL) free(OutPutData);
154
156 InputData=createRBuffer(RBuffer);
157 OutPutData=createRBuffer(RBuffer);
158
159 for (int i=0;i<exp-1;i++)
160 {
161 MultipTwo(OutPutData,*InputData);
162 }
163 printnum(*OutPutData);
165 //Used for eclipse debug
166 fflush(stdout);
168 }
169 return 0;
170 }
