Roman To Integer LEET CODE














































Roman To Integer LEET CODE



Roman numerals are represented by seven different symbols: IVXLCD and M.

Symbol       Value
I             1
V             5
X             10
L             50
C             100
D             500
M             1000

For example, 2 is written as in Roman numeral, just two one's added together. 12 is written as, which is simply X + II. The number 27 is written as, which is XX + V + II.

Roman numerals are usually written largest to smallest from left to right. However, the numeral for four is not IIII. Instead, the number four is written as IV. Because the one is before the five we subtract it making four. The same principle applies to the number nine, which is written as IX. There are six instances where subtraction is used:

  • I can be placed before V (5) and X (10) to make 4 and 9. 
  • X can be placed before L (50) and C (100) to make 40 and 90. 
  • C can be placed before D (500) and M (1000) to make 400 and 900.

Example 1:

Input: s = "IV"
Output: 4

Example 2:

Input: s = "IX"
Output: 9

Example 3:

Input: s = "MCMXCIV"
Output: 1994
Explanation: M = 1000, CM = 900, XC = 90 and IV = 4.

code :

def RomanToInt(s) :

        #Use dictionary for pre assigned values
        d = {"I":1,"V":5,"X":10,"L":50,"C":100,"D":500,"M":1000}
        sum1 = 0

        #for having a track of previous value
        prev = 0
        for i in s:
            if d[i] > prev :
                sum1 = sum1 + (d[i] - 2*(prev))
                prev = d[i]
            
            else:
                sum1 = sum1 + d[i]
                prev = d[i]
            
        return sum1

     This Article is written by Rohit Bansal.



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