Leet Code Problem-Easy

Today, i am starting my journey from leetcode-easy . Here the Problem is to Convert Roman to an Integer.

Problem Link- https://leetcode.com/problems/roman-to-integer/

Approach -We have to keep the conditions in mind. When we traverse the string from left to right, we have to check that if we encounter a small value compared to the next value(i<i+1), we have to subtract the current value from a global value(It is defined globally with 0)[gloabl-=currentvalue] else addition.

Note- we have to add a condition if reach the last value of the string then the condition should be added (i<string length -1)

Here Jave Solution

class Solution {

public int romanToInt(String s) {

//map of roman value

Map<Character, Integer> rmInt=new HashMap<Character, Integer>();

rmInt.put(‘I’,1);

rmInt.put(‘V’,5);

rmInt.put(‘X’,10);

rmInt.put(‘L’,50);

rmInt.put(‘C’,100);

rmInt.put(‘D’,500);

rmInt.put(‘M’,1000);

int ans=0; //global value

for(int i=0;i<s.length();i++){

if( i<s.length()-1 && rmInt.get(s.charAt(i))<rmInt.get(s.charAt(i+1)) ) // check the value with condition

ans-=rmInt.get(s.charAt(i));

else

ans+=rmInt.get(s.charAt(i));

}

return ans; //return the current value

}

}

Input-1

s =

“III”

Output

3

Expected

3

Input-2

s =“LVIII”

Output

58

Expected

58

Input-3

s =“MCMXCIV”

Output

1994

Expected

1994