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Convert Roman to Integer

Certification: Basic Level Accuracy: 0% Submissions: 0 Points: 5

Write a JavaScript program to convert a Roman numeral string to its integer equivalent. Roman numerals are represented by seven symbols: I = 1, V = 5, X = 10, L = 50, C = 100, D = 500, M = 1000. Roman numerals are usually written from largest to smallest from left to right. However, in some cases, a smaller numeral appears before a larger one to indicate subtraction (e.g., IV = 4, IX = 9).

Example 1
    
  
  • Input: s = "LVIII"
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  • Output: 58
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  • Explanation: 
    • Break down the Roman numeral: L = 50, V = 5, I = 1, I = 1, I = 1. 
    • Since all symbols are in descending order, simply add them. 
    • 50 + 5 + 1 + 1 + 1 = 58. 
    • Therefore, "LVIII" equals 58.
    •
Example 2
    
  
  • Input: s = "MCMXC"
    • 
  
  • Output: 1990
    • 
  
  • Explanation: 
    • Break down the Roman numeral: M = 1000, C = 100, M = 1000, X = 10, C = 100. 
    • CM represents 1000 - 100 = 900 (subtraction case). 
    • XC represents 100 - 10 = 90 (subtraction case). 
    • M + CM + XC = 1000 + 900 + 90 = 1990. 
    • Therefore, "MCMXC" equals 1990.
    •
Constraints
    
  
  • 1 ≤ s.length ≤ 15
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  • s contains only the characters ('I', 'V', 'X', 'L', 'C', 'D', 'M')
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  • It is guaranteed that s is a valid Roman numeral in the range [1, 3999]
    • 
  
  • Time Complexity: O(n)
    • 
  
  • Space Complexity: O(1)
    •
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Hint
Solution

Solution Hints

    
  
  • Create a mapping of Roman symbols to their integer values
    • 
  
  • Iterate through the string from left to right
    • 
  
  • For each character, check if the next character represents a larger value
    • 
  
  • If the current value is smaller than the next, subtract it (subtraction case)
    • 
  
  • Otherwise, add the current value to the result
    • 
  
  • Handle the last character separately as it has no next character
    •

Steps to solve by this approach:

 Step 1: Create a mapping object that associates each Roman symbol with its integer value.
 Step 2: Initialize a result variable to store the final integer value.
 Step 3: Iterate through each character in the Roman numeral string.
 Step 4: For each character, get its value and the value of the next character (if it exists).
 Step 5: If the current value is less than the next value, subtract it from the result (subtraction case).
 Step 6: Otherwise, add the current value to the result (normal case).
 Step 7: Return the final result after processing all characters.

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