Total Appeal of a String

class Solution {
public:
    long long appealSum(string s) {
        long long ans = 0, cur = 0;
        vector<int> last(26, -1);
        for (int i = 0; i < (int)s.size(); ++i) {
            int c = s[i] - 'a';
            cur += i - last[c];
            ans += cur;
            last[c] = i;
        }
        return ans;
    }
};

func appealSum(s string) int64 {
  var ans, cur int64
  last := [26]int{}
  for i := range last {
    last[i] = -1
  }
  for i := 0; i < len(s); i++ {
    c := int(s[i] - 'a')
    cur += int64(i - last[c])
    ans += cur
    last[c] = i
  }
  return ans
}

class Solution:
    def appealSum(self, s: str) -> int:
        ans = 0
        cur = 0
        last = [-1] * 26
        for i, ch in enumerate(s):
            c = ord(ch) - ord('a')
            cur += i - last[c]
            ans += cur
            last[c] = i
        return ans

var appealSum = function(s) {
    let ans = 0, cur = 0;
    const last = new Array(26).fill(-1);
    for (let i = 0; i < s.length; i++) {
        const c = s.charCodeAt(i) - 97;
        cur += i - last[c];
        ans += cur;
        last[c] = i;
    }
    return ans;
};

class Solution {
    public long appealSum(String s) {
        long ans = 0, cur = 0;
        int[] last = new int[26];
        Arrays.fill(last, -1);
        for (int i = 0; i < s.length(); i++) {
            int c = s.charAt(i) - 'a';
            cur += i - last[c];
            ans += cur;
            last[c] = i;
        }
        return ans;
    }
}

function appealSum(s: string): number {
    let ans: number = 0, cur: number = 0;
    const last: number[] = new Array(26).fill(-1);
    for (let i = 0; i < s.length; i++) {
        const c: number = s.charCodeAt(i) - 97;
        cur += i - last[c];
        ans += cur;
        last[c] = i;
    }
    return ans;
}