[LeetCode]Fraction to Recurring Decimal

Given two integers representing the numerator and denominator of a fraction, return the fraction in string format.

If the fractional part is repeating, enclose the repeating part in parentheses.

For example,

• Given numerator = 1, denominator = 2, return "0.5".
• Given numerator = 2, denominator = 1, return "2".
• Given numerator = 2, denominator = 3, return "0.(6)".

  Credits:
  Special thanks to @Shangrila for adding this problem and creating all test cases.

  
  

  
  

  
  

  public class Solution {
  	class Pair{
  		@Override
  		public int hashCode() {
  			final int prime = 31;
  			int result = 1;
  			result = prime * result + getOuterType().hashCode();
  			result = prime * result + ans;
  			result = prime * result + mod;
  			return result;
  		}
  		@Override
  		public boolean equals(Object obj) {
  			if (this == obj)
  				return true;
  			if (obj == null)
  				return false;
  			if (getClass() != obj.getClass())
  				return false;
  			Pair other = (Pair) obj;
  			if (!getOuterType().equals(other.getOuterType()))
  				return false;
  			if (ans != other.ans)
  				return false;
  			if (mod != other.mod)
  				return false;
  			return true;
  		}
  		int mod;
  		int ans;
  		Pair(int mod,int ans){
  			this.mod = mod;
  			this.ans = ans;
  		}
  		private Solution getOuterType() {
  			return Solution.this;
  		}
  	}
      public String fractionToDecimal(int numerator, int denominator) {
          if(numerator == 0) return "0";
          int ans = numerator/denominator;
          int mod = numerator%denominator;
          if(mod == 0) return ans+"";
          StringBuilder sb = new StringBuilder();
          sb.append(ans+".");
          Map
      
        map = new HashMap<>();
          while(mod!=0){
          	ans = (10*mod)/denominator;
          	mod = (10*mod)%denominator;
          	Pair p = new Pair(mod,ans);
          	if(map.containsKey(p)){
          		sb.insert(map.get(p)-1, "(");
          		sb.append(")");
          		break;
          	}else if(mod == 0){
          		sb.append(ans);
          		break;
          	}
          	sb.append(ans);
          	map.put(p, sb.length());
          }
          return sb.toString();
      }
  }