Roman to Integer

class Solution {
public:
    int romanToInt(string s) {
        unordered_map<char,int> v = {{'I',1},{'V',5},{'X',10},{'L',50},{'C',100},{'D',500},{'M',1000}};
        int n = s.size(), ans = 0;
        for (int i = 0; i < n; ++i) {
            if (i + 1 < n && v[s[i]] < v[s[i+1]]) ans -= v[s[i]];
            else ans += v[s[i]];
        }
        return ans;
    }
};

func romanToInt(s string) int {
    v := map[byte]int{'I': 1, 'V': 5, 'X': 10, 'L': 50, 'C': 100, 'D': 500, 'M': 1000}
    n, ans := len(s), 0
    for i := 0; i < n; i++ {
        if i+1 < n && v[s[i]] < v[s[i+1]] {
            ans -= v[s[i]]
        } else {
            ans += v[s[i]]
        }
    }
    return ans
}

class Solution:
    def romanToInt(self, s: str) -> int:
        v = {'I': 1, 'V': 5, 'X': 10, 'L': 50, 'C': 100, 'D': 500, 'M': 1000}
        n, ans = len(s), 0
        for i in range(n):
            if i + 1 < n and v[s[i]] < v[s[i + 1]]:
                ans -= v[s[i]]
            else:
                ans += v[s[i]]
        return ans

function romanToInt(s) {
    const v = { I: 1, V: 5, X: 10, L: 50, C: 100, D: 500, M: 1000 };
    const n = s.length;
    let ans = 0;
    for (let i = 0; i < n; i++) {
        if (i + 1 < n && v[s[i]] < v[s[i + 1]]) ans -= v[s[i]];
        else ans += v[s[i]];
    }
    return ans;
}

class Solution {
    public int romanToInt(String s) {
        Map<Character, Integer> v = new HashMap<>();
        v.put('I', 1); v.put('V', 5); v.put('X', 10); v.put('L', 50);
        v.put('C', 100); v.put('D', 500); v.put('M', 1000);
        int n = s.length(), ans = 0;
        for (int i = 0; i < n; i++) {
            if (i + 1 < n && v.get(s.charAt(i)) < v.get(s.charAt(i + 1))) ans -= v.get(s.charAt(i));
            else ans += v.get(s.charAt(i));
        }
        return ans;
    }
}

function romanToInt(s: string): number {
    const v: Record<string, number> = { I: 1, V: 5, X: 10, L: 50, C: 100, D: 500, M: 1000 };
    const n = s.length;
    let ans = 0;
    for (let i = 0; i < n; i++) {
        if (i + 1 < n && v[s[i]] < v[s[i + 1]]) ans -= v[s[i]];
        else ans += v[s[i]];
    }
    return ans;
}