### equalCountSubstrings 
from typing import *
def f_gold(s: str, count: int) -> int:
    n = len(s)
    if count > n:
        return 0
    counter = [[0] * 26 for _ in range(n + 1)]
    def check(i, j):
        c1 = counter[i]
        c2 = counter[j + 1]
        for k in range(26):
            if c2[k] == 0 or c1[k] == c2[k]:
                continue
            if c2[k] - c1[k] != count:
                return False
        return True
    ans = 0
    for i, c in enumerate(s):
        idx = ord(c) - ord('a')
        for j in range(26):
            counter[i + 1][j] = counter[i][j]
        counter[i + 1][idx] = counter[i][idx] + 1
        l = 0
        for _ in range(26):
            l += count
            j = i - l + 1
            if j < 0:
                break
            ans += check(j, i)
    return ans