Special Subsequences "AG"

1 <= length(A) <= 10^5

First and only argument is a string A.

Return an integer denoting the answer.

Input 1:
A = "ABCGAG"

Input 2:
A = "GAB"

Output 1:
3

Output 2:
0

Explanation 1:
Subsequence "AG" is 3 times in given string

Explanation 2:
There is no subsequence "AG" in the given string.

public class Solution {
    public int countAG(String A) {
        int MOD = 1000000007;
        int count = 0;
        int countA = 0;
 
        for (char c : A.toCharArray()) {
            if (c == 'A') {
                countA++;
            } else if (c == 'G') {
                count = (count + countA) % MOD;
            }
        }
        return count;
    }
}

MOD = 10**9 + 7
 
def countAG(A):
    count = 0
    countA = 0
 
    for c in A:
        if c == 'A':
            countA += 1
        elif c == 'G':
            count = (count + countA) % MOD
 
    return count

function countAG(A) {
    const MOD = 1000000007;
    let count = 0;
    let countA = 0;
 
    for (let i = 0; i < A.length; i++) {
        if (A[i] === 'A') {
            countA++;
        } else if (A[i] === 'G') {
            count = (count + countA) % MOD;
        }
    }
 
    return count;
}