Given an array A of positive integers, call a (contiguous, not necessarily distinct) subarray of A good if the number of different integers in that subarray is exactly K.
(For example, [1,2,3,1,2] has 3 different integers: 1, 2, and 3.)
Return the number of good subarrays of A.
 
Example 1:
Input: A = [1,2,1,2,3], K = 2
Output: 7
Explanation: Subarrays formed with exactly 2 different integers: [1,2], [2,1], [1,2], [2,3], [1,2,1], [2,1,2], [1,2,1,2].

Example 2:
Input: A = [1,2,1,3,4], K = 3
Output: 3
Explanation: Subarrays formed with exactly 3 different integers: [1,2,1,3], [2,1,3], [1,3,4].

 
Note:

1 <= A.length <= 20000
1 <= A[i] <= A.length
1 <= K <= A.length

```python

USER_FILENAME = "<user_code>"
import sys, json, builtins
import math, heapq, bisect, itertools, functools, collections, statistics, fractions, decimal, operator, array, random, re, string, os, pathlib
try:
    import resource as _res
except Exception:
    _res = None
from collections import Counter, defaultdict, deque, OrderedDict
from functools import lru_cache, reduce
from itertools import accumulate, permutations, combinations, product
from math import gcd, ceil, floor, sqrt
from decimal import Decimal
try:
    from typing import *
except Exception:
    pass
try:
    sys.setrecursionlimit(1_000_000)
except Exception:
    pass
try:
    import site as _site
    try:
        _sys_sites = _site.getsitepackages() if hasattr(_site, "getsitepackages") else []
        for _p in _sys_sites:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
    try:
        _usp = _site.getusersitepackages()
        if isinstance(_usp, str):
            _usp = [_usp]
        for _p in _usp:
            if _p and _p not in sys.path:
                sys.path.append(_p)
    except Exception:
        pass
except Exception:
    pass

def _disabled_input(*args, **kwargs):
    raise RuntimeError("input() is disabled in callable mode")
builtins.input = _disabled_input

ns = {"__name__": "__judge__"}  # prevent if __name__ == "__main__" blocks
for _k, _v in list(globals().items()):
    if not _k.startswith("_"):
        ns[_k] = _v
_CODE = 'class Solution:\n    \n    def _identify_limit(self, A, current_limit, K,  char_count_after_limit):\n        # unique_chars = {i for i in char_count_after_limit if char_count_after_limit[i] > 0}\n        # print(unique_chars)\n        temp_char = A[current_limit]\n        while char_count_after_limit.get(temp_char, 0) > 1 : \n            # print(\\"WHILE\\", char_count_after_limit)\n            char_count_after_limit[temp_char] = char_count_after_limit[temp_char] - 1\n            current_limit += 1\n            temp_char = A[current_limit]\n            \n\n        return  current_limit , char_count_after_limit\n    \n    def subarraysWithKDistinct(self, A: List[int], K: int) -> int:\n        char_info = {item : [] for item in set(A)} \n        unique_char_count = {}\n        unique_char = set()\n        start_idx = 0 \n        end_idx = 0\n        num_substr = 0\n        current_subarray = []\n        current_valid_count = 0 \n        # In any valid subarray what is the index upto which left index could be moved without making subarray bad \n        # Whenever end_idx is moved to right keeping subarray good compute limit_idx again \n        limit_idx = 0\n        while end_idx < len(A) + 1 : \n            if len(unique_char_count) == K : \n                limit_idx, unique_char_count = self._identify_limit(A, limit_idx, K, unique_char_count)\n                num_substr += limit_idx - start_idx + 1\n                if end_idx < len(A):\n                    current_char = A[end_idx]\n                    unique_char_count[current_char] = unique_char_count.get(current_char, 0) + 1\n                end_idx += 1 \n            elif len(unique_char_count) > K: \n                # Remove limit_idx from stats\n                current_char = A[limit_idx]\n                unique_char_count.pop(current_char)\n                start_idx = limit_idx + 1\n                limit_idx = start_idx \n            else: \n                if end_idx < len(A):\n                    current_char = A[end_idx]\n                    unique_char_count[current_char] = unique_char_count.get(current_char, 0) + 1\n                end_idx += 1 \n        return num_substr\n\n    \n    \n    #         counter1, counter2 = collections.Counter(), collections.Counter()\n#         slow = fast = res = 0\n\n#         for _, a in enumerate(A):\n#             counter1[a], counter2[a] = counter1[a] + 1, counter2[a] + 1\n#             while len(counter2) == K:\n#                 counter2[A[fast]] -= 1\n#                 if not counter2[A[fast]]: del counter2[A[fast]]\n#                 fast += 1\n#             while len(counter1) > K:\n#                 counter1[A[slow]] -= 1\n#                 if not counter1[A[slow]]: del counter1[A[slow]]\n#                 slow += 1\n#             res += fast - slow\n\n#         return res\n'
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'subarraysWithKDistinct'
if _fn_name:
    if "Solution" in ns:
        try:
            _obj = ns["Solution"]()
            if hasattr(_obj, _fn_name):
                _target = getattr(_obj, _fn_name)
        except Exception:
            _target = None
    if _target is None and _fn_name in ns and callable(ns[_fn_name]):
        _target = ns[_fn_name]
# Fallback: if there's exactly one user-defined function, use it
if _target is None:
    _cands = [v for k, v in ns.items() if callable(v) and getattr(v, "__module__", "") in ("__judge__", "__main__")]
    _user_funcs = [c for c in _cands if getattr(c, "__name__", "").startswith("_") is False]
    if len(_user_funcs) == 1:
        _target = _user_funcs[0]
if _target is None:
    raise RuntimeError(f"Could not resolve callable '{_fn_name}'")

_raw = sys.stdin.read().strip()
if _raw:
    _parsed = json.loads(_raw)
    if isinstance(_parsed, dict):
        _kwargs = _parsed.get("kwargs", {})
        _args = _parsed.get("args", [])
    else:
        _args, _kwargs = _parsed, {}
else:
    _args, _kwargs = [], {}
if not isinstance(_args, (list, tuple)):
    _args = [_args]
_res = _target(*_args, **_kwargs)
try:
    sys.stdout.write(repr(_res) + "\n")
except Exception:
    pass

```

Measured memory_bytes: 6824