leetcode166. Fraction to recurring Decimal

Test instructions: The numerator and denominator are given, the result is represented by a string, and the part of the loop is enclosed in "()".

Ideas:

Analog written calculation,

Initially, based on the 1/99 scenario, it is envisaged to record the interval step of the remainder with the path, but only for processing (00). 0n) where n is [1,9];

Later took the online see with Map records < remainder, appeared position > idea.

By judging whether the key in the map is repeated to determine whether the loop, through the key corresponding to the occurrence of the position, to determine the number of circular bits.

List of loggers.

Attention:

The case where the divisor is 0;

A case in which the divisor is min_int; (with long processing)

The result is a negative case;

Only a positive number of cases.

Code:

1 classSolution {2  Public:3     stringFractiontodecimal (intNumerator,intdenominator) {4         LongBei =numerator;5         LongChu =denominator;6         intFuflag =0;7         if(chu<0)8         {9Chu *=-1;TenBei *=-1; One         } A         if(bei<0) -         { -Fuflag =1; theBei *=-1; -         } -         if(bei==0) -             return "0"; +map<Long,Long>Mymap; -vector<Long>Shangvec; +         LongYup =0; A         LongFirstflag =1; at          while(bei) -         { -             if(Firstflag = =0) -Bei *=Ten; -Firstflag =0; -             LongTMP = bei/Chu; in             LongYu = bei-tmp *Chu; - Shangvec.push_back (TMP); tomap<Long,Long>:: iterator it; +it =Mymap.find (Yu); -             if(it!=mymap.end ()) the             { *                 LongXUNP = it->second; $                 stringAns ="";Panax Notoginseng                 if(Fuflag) -Ans + ="-"; the ostringstream S1; +s1<<shangvec[0]; AAns + =s1.str (); theS1.STR (""); +Ans + ="."; -                  for(LongI=1; i<=xunp;i++) $                 { $s1<<Shangvec[i]; -Ans + =s1.str (); -S1.STR (""); the                 } -Ans + ="(";Wuyi                  for(Longi=xunp+1; I<shangvec.size (); i++) the                 { -s1<<Shangvec[i]; WuAns + =s1.str (); -S1.STR (""); About                 } $Ans + =")"; -                 returnans; -             } -Mymap[yu] = yup++; ABei =Yu; +         } the         stringAns =""; -         if(Fuflag) $Ans + ="-"; the ostringstream S1; thes1<<shangvec[0]; theAns + =s1.str (); theS1.STR (""); -         if(shangvec.size () = =1) in             returnans; the  theAns + ="."; About          for(intI=1; I<shangvec.size (); i++) the         { thes1<<Shangvec[i]; theAns + =s1.str (); +S1.STR (""); -         } the         returnans;Bayi     } the};

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leetcode166. Fraction to recurring Decimal