Leetcode•Sep 03, 2025
Fraction to Recurring Decimal
Hazrat Ali
Leetcode
If the fractional part is repeating, enclose the repeating part in parentheses.
If multiple answers are possible, return any of them.
It is guaranteed that the length of the answer string is less than 104 for all the given inputs.
Example 1:
Input: numerator = 1, denominator = 2 Output: "0.5"
Example 2:
Input: numerator = 2, denominator = 1 Output: "2"
Example 3:
Input: numerator = 4, denominator = 333 Output: "0.(012)"
Solution
/**
* @param {number} numerator
* @param {number} denominator
* @return {string}
*/
const fractionToDecimal = (numerator, denominator) => {
if (denominator === 0) {
return 'NaN';
}
if (numerator === 0) {
return '0';
}
const result = [];
if ((numerator < 0) ^ (denominator < 0)) {
result.push('-');
}
const n = Math.abs(numerator);
const d = Math.abs(denominator);
result.push(Math.floor(n / d));
if (n % d == 0) {
return result.join('');
}
result.push('.');
const map = new Map();
for (let r = n % d; r > 0; r %= d) {
if (map.has(r)) {
result.splice(map.get(r), 0, '(');
result.push(')');
break;
}
map.set(r, result.length);
r *= 10;
result.push(Math.floor(r / d));
}
return result.join('');
};
const result = fractionToDecimal(1, 333);
console.log(result);