High-Precision power

High-Precision power

Personal information: He is a junior majoring in software engineering at yanda University;

My blog: Google searches for "cqs_2012;

My hobbies: I love data structures and algorithms and hope to make my own contribution to algorithm work in the future;

Programming Language: C ++;

Programming Environment: Windows 7 Professional Edition x64;

Programming tools: vs2008;

Drawing tools: Office 2010 PowerPoint;

Hardware information: 7g-3 Notebook;

Zhenyan

Go to the flame Hill, and then refine the red eye

Question

1001 Power Operation

Web http://bailian.openjudge.cn/practice/1001/

Solution

String processing.

I am not very familiar with this system. After multiple attempts, I found that this system is not compatible with many things, as shown below:

System ("pause ");

<Windows. h>

For input and output control, the number of input and output cannot be specified according to the example given, while (CIN>) is used to control whether to continue the input.

Ah, a tear.

Question: this is a power operation. It is not difficult to calculate high-precision computation. Consider integer overflow and use the string to simulate integer computation.

Algorithm

The personal algorithm is represented as follows in C ++ code (some of the Code has used previously written programs, so it looks messy, but the code written only by the individual is not copied)

# Include <iostream> # include <string> using namespace STD; // decimal power string floatpower (string a, unsigned int B); bool xiaoshucheck (string ); bool check_all_number (string a); // fractional multiplication string floatm ult (string a, string B); STD: pair <string, int> standardxiaoshu (string ); string mult_int (string a, string B); bool standardization (string & A); string inttochar (int I); int chartonumber (char C); string add_int (string a, STR Ing B); string addint (string a, string B); string subint (string a, string B); char compare (string a, string B); char comparexiaoshu (string, string B); // The decimal power string floatpower (string a, unsigned int B) {If (! A. empty () & xiaoshucheck (A) {string result = "1"; for (unsigned int I = B-1; I <B; I --) {result = floatm ult (, result);} If (result [0] = '0' & Result [1] = '. ') Result = result. substr (1, result. length ()-1); return result;} else if (! A. Empty ()&&! Xiaoshucheck (A) {string result = "1"; for (unsigned int I = B-1; I <B; I --) {result = mult_int (A, result );} return result ;}} bool xiaoshucheck (string a) {bool Xiaoshu = false; string B = A; // find the decimal point for (unsigned int I = 0; I <B. length (); I ++) if (B [I] = '. ') {Xiaoshu = true; // after removing the decimal point, determine whether the integer Form B = B. substr (0, I) + B. substr (I + 1, B. length ()-i-1); If (check_all_number (B )! = True) Xiaoshu = false; break;} return Xiaoshu;} // decimal multiplication string floatm ult (string a, string B) {// extend the decimal number to an integer, then perform the following operations: // (A * B)/(sum of decimal points) // STD: pair <string, int> SA = standardxiaoshu (a); STD :: pair <string, int> Sb = standardxiaoshu (B); A = sa. first; B = sb. first; // a * B. The enlarged result is string r = mult_int (a, B). // What should I do if the result is negative? Convert it to bool fushu = false; If (R [0] = '-') {fushu = true; r = R. substr (1, R. length ()-1);} // The result produces many zeros, and the decimal length is greater than 0 unsigned int maxlength = sa. second + sb. second; while (R [R. length ()-1] = '0' & maxlength> 0) {r = R. substr (0, R. length ()-1); maxlength --;} // if the result is decimal and smaller than 1, add 0 while (R. length () <= maxlength) {r = "0" + R;} If (maxlength = 0 | compare (R. substr (R. length ()-maxlength, maxlength), "0") = ') r = R. SUBST R (0, R. length ()-maxlength); else // Add the decimal point R = R. substr (0, R. length ()-maxlength) + ". "+ R. substr (R. length ()-maxlength, maxlength); // What if the result is negative? If (fushu = true) r = '-' + R; // return result return r ;} bool check_all_number (string a) {if (. empty () return false; string: size_type L =. size (), I = 0; if (a [0] = '-') I ++; while (I <L) {if (a [I] <'0' | A [I]> '9') return false; I ++;} return true;} STD :: pair <string, int> Standard Xiaoshu (string a) {// data domain bool fushu = false; string B; unsigned int I; // check whether a is a decimal if (a [0] = '-') {fushu = true; A =. substr (1,. length ()-1);} // A is a decimal if (xiaoshucheck (A) = true) {// remove 0 at the end of the decimal part while (true) {if (a [. length ()-1] = '0') A =. substr (0,. length ()-1); else break;} // remove the first 0 of the integer from for (I = 0; I <. length (); I ++) if (a [I] = '. ') {B =. substr (0, I); A =. substr (I + 1,. length ()-i-1); break;} standardization (B); = B + A; I =. length ()-B. length (); If (fushu = true) A = "-" + A; // return STD: make_pair (A, I );} // A is an integer else if (check_all_number (A) = true) {standardization (a); If (fushu = true) A = "-" + A; return STD:: make_pair (A, 0) ;}} string mult_int (string a, string B) {// exception of inputif (. empty () return B; else if (B. empty () Return "0"; if (! Check_all_number (a) |! Check_all_number (B) {return "exception of input multiplies_int";} standardization (a); Standardization (B); string: size_type I =. size (), j = B. size (); string c = "0", D = ""; bool fushu = (a [0] = '-' & B [0]! = '-') | (A [0]! = '-' & B [0] = '-'); if (a [0] = '-') A =. substr (1,. size (); If (B [0] = '-') B = B. substr (1, B. size (); int Jinwei = 0; For (j = B. size ()-1; j <B. size (); j --) {// each number of B to * A Jinwei = 0; for (I =. size ()-1; I <. size (); I --) {d = inttochar (chartonumber (A [I]) * chartonumber (B [J]) + Jinwei) % 10) + d; jinwei = (chartonumber (A [I]) * chartonumber (B [J]) + Jinwei)/10;} If (Jinwei) d = I Nttochar (Jinwei) + d; // Add all number resultc = add_int (c, d); D = ""; unsigned int zero = 0; while (zero <B. size ()-j) {d = d + '0'; zero ++ ;}} standardization (c); If (fushu & C! = "0") return '-' + C; else return C;} bool standardization (string & A) {If (! Check_all_number (A) {cout <A <"exception of input standardization" <Endl; return false;} string: size_type I = 0; bool fushu = false; if (A [0] = '-') {fushu = true; I = 1;} while (I <. size () {if (a [I]! = '0') break; I ++;} if (I =. size () I --; A =. substr (I,. size ()-I); If (fushu &! = "0") A = '-' + A; return true;} string inttochar (int I) {if (I> = 0 & I <= 9) {string c = ""; return C + char (I + 48);} else {cout <I <"exception of input inttochar" <Endl; return "E" ;}}// make Char to the int numberint chartonumber (char c) {If (C> = '0' & C <= '9 ') return int (c-'0'); else {cout <C <"exception of input chartonumber" <Endl; return 0 ;}; string add_int (string, string B) {// exception of I Nputif (A. Empty () return B; else if (B. Empty () Return "0"; if (! Check_all_number (a) |! Check_all_number (B) {return "exception of input add_int";} standardization (a); Standardization (B); if (a [0]! = '-' & B [0]! = '-') Return addint (a, B); else if (a [0]! = '-' & B [0] = '-') return subint (A, B. substr (1, B. size (); else if (a [0] = '-' & B [0]! = '-') Return subint (B,. substr (1,. size (); else return '-' + addint (. substr (1,. size (), B. substr (1, B. size () ;}; string subint (string a, string B) {// exception of inputif (! Check_all_number (a) |! Check_all_number (B) Return "exception of input minusint"; Standardization (a); Standardization (B); // participant ular string of inputif (. empty () {If (B. empty () Return "0"; elsereturn "-" + B;} else if (B. empty () {return a;} // normal number A <bstring c = ""; bool check = true; If (compare (a, B) = ') return "0"; else if (compare (a, B) = '<') {c = A; A = B; B = C; C = ""; check = false;} // normal number A> = bstring:: Size_type I =. size ()-1, j = B. size ()-1; int jiewei = 0, now; while (I <. size () & J <B. size () {now = chartonumber (A [I])-chartonumber (B [J])-jiewei; If (now <0) {jiewei = 1; now = 10 + now;} else jiewei = 0; C = inttochar (now) + C; I --; j --;} while (I <. size () {now = chartonumber (A [I])-jiewei; If (now <0) {jiewei = 1; now = 10 + now;} else jiewei = 0; C = inttochar (now) + C; I --;} standardizat Ion (c); If (! Check) C = '-' + C; return C ;}; string addint (string a, string B) {// exception of inputif (. empty () return B; else if (B. empty () Return "0"; if (! Check_all_number (a) |! Check_all_number (B) {return "exception of input addint";} standardization (a); Standardization (B); string: size_type I =. size ()-1, j = B. size ()-1, K = 0; string c = ""; int Jinwei = 0; while (I <. size () & J <B. size () {c = inttochar (chartonumber (A [I]) + chartonumber (B [J]) + Jinwei) % 10) + C; jinwei = (chartonumber (A [I]) + chartonumber (B [J]) + Jinwei)/10; j --; I --;} while (j <B. size () {c = Inttochar (chartonumber (B [J]) + Jinwei) % 10) + C; Jinwei = (Jinwei + chartonumber (B [J])/10; j --;} while (I <. size () {c = inttochar (chartonumber (A [I]) + Jinwei) % 10) + C; Jinwei = (Jinwei + chartonumber (A [I]) /10; I --;} If (Jinwei) C = inttochar (Jinwei) + C; Standardization (c); Return C ;}; char compare (string a, string B) {if (. empty () | B. empty () {cout <"error of input compare"; retu Rn 'E';} else {If (! Check_all_number (a) |! Check_all_number (B) {return 'E';} standardization (a); Standardization (B); if (a [0] = '-' & B [0]! = '-') Return '<'; else if (a [0]! = '-' & B [0] = '-') return '>'; bool fushu = (a [0] = '-'); if (. size ()> B. size () return fushu? '<': '>'; Else if (. size () = B. size () {for (string: size_type I = 0; I <. size (); I ++) {if (a [I]> B [I]) return fushu? '<': '>'; If (a [I] <B [I]) return fushu? '>': '<';} Return '=';} return fushu? '>': '<';} Char comparexiaoshu (string a, string B) {If (xiaoshucheck (a) & xiaoshucheck (B) {pair <string, int> SA = standardxiaoshu (a); pair <string, int> Sb = standardxiaoshu (B); int length = sa. second-Sb. second; while (length! = 0) {If (length <0) {SA. first + = "0"; length ++;} else if (length> 0) {sb. first + = "0"; Length --;} return compare (SA. first, sb. first) ;}}int main () {string a; int B; while (CIN >>>a> B) cout <floatpower (a, B) <Endl; // system ("pause"); Return 0 ;}