easy

Roman to Integer

To convert a Roman numeral to an integer in JavaScript, you can follow these steps:

1. Create a dictionary object to map each Roman symbol to its corresponding value.
2. Initialize a variable result to store the final integer value.
3. Iterate through the Roman numeral string from left to right.
4. Check if the current symbol is less than the next symbol. If so, subtract the current value from the result. Otherwise, add the current value to the result.
5. Return the final result.

Here's the JavaScript code implementation:

function romanToInt(s) {
  const symbolValues = {
    I: 1,
    V: 5,
    X: 10,
    L: 50,
    C: 100,
    D: 500,
    M: 1000,
  };
 
  let result = 0;
 
  for (let i = 0; i < s.length; i++) {
    const currentSymbolValue = symbolValues[s[i]];
    const nextSymbolValue = symbolValues[s[i + 1]];
 
    if (nextSymbolValue && currentSymbolValue < nextSymbolValue) {
      result -= currentSymbolValue;
    } else {
      result += currentSymbolValue;
    }
  }
 
  return result;
}
 
// Example usage:
console.log(romanToInt("III")); // Output: 3
console.log(romanToInt("IV")); // Output: 4
console.log(romanToInt("IX")); // Output: 9
console.log(romanToInt("LVIII")); // Output: 58
console.log(romanToInt("MCMXCIV")); // Output: 1994

The time complexity of this solution is O(n), where n is the length of the input Roman numeral string. The space complexity is** O(1)** since we are using a constant amount of space regardless of the input size.