In a 1 million by 1 million grid, the coordinates of each grid square are (x, y) with 0 <= x, y < 10^6.
We start at the source square and want to reach the target square.  Each move, we can walk to a 4-directionally adjacent square in the grid that isn't in the given list of blocked squares.
Return true if and only if it is possible to reach the target square through a sequence of moves.
 
Example 1:
Input: blocked = [[0,1],[1,0]], source = [0,0], target = [0,2]
Output: false
Explanation: 
The target square is inaccessible starting from the source square, because we can't walk outside the grid.

Example 2:
Input: blocked = [], source = [0,0], target = [999999,999999]
Output: true
Explanation: 
Because there are no blocked cells, it's possible to reach the target square.

 
Note:

0 <= blocked.length <= 200
blocked[i].length == 2
0 <= blocked[i][j] < 10^6
source.length == target.length == 2
0 <= source[i][j], target[i][j] < 10^6
source != target

```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    def isEscapePossible(self, blocked: List[List[int]], source: List[int], target: List[int]) -> bool:\n\n        #Column and row of source and target (used for escape condition)\n        sc, sr = source\n        tc, tr = target\n        R, C = 10**6, 10**6\n\n        def dist(r1,c1,r2,c2):\n            '''Calculates Manhattan distance from (r1,c1) to (r2,c2)'''\n            return abs(r2-r1)+abs(c2-c1)\n\n        #Two priority queues: one starting from target and one from source\n        #Two visited sets: one for nodes visited by path from target and the other from source\n        q = [[(0,*source[::-1])], [(0,*target[::-1])]]\n        v = [set(),set()]\n        b = set((tuple(b[::-1]) for b in blocked))\n\n        if (tuple(source) in b) or (tuple(target) in b):\n            return False\n\n        #if source and target can reach 200 distance from their origin\n        #it is safe to say 200 blocked spaces cannot contain them\n        source_escape = False\n        target_escape = False\n\n        while q[0] and q[1]:\n\n            index = 0 if len(q[0]) <= len(q[1]) else 1\n\n            d, r, c = heapq.heappop(q[index])\n\n            for i, j in ((r+1, c), (r-1, c), (r, c+1), (r, c-1)):\n                if (0 <= i < R) and (0 <= j < C) and ((i,j) not in b) and ((i,j) not in v[index]):\n\n                    if (i,j) in v[1-index]:\n                        return True\n\n                    v[index].add((i,j))\n                    r_target, c_target = q[1-index][0][1:]\n                    heapq.heappush(q[index], (dist(i,j,r_target,c_target), i, j))\n\n            if not source_escape and not index:\n                source_escape = dist(r, c, sr, sc) > 200\n            if not target_escape and index:\n                target_escape = dist(r, c, tr, tc) > 200\n\n            if source_escape and target_escape:\n                return True\n\n        return False\n"
_co = compile(_CODE, USER_FILENAME, "exec")
exec(_co, ns, ns)

_target = None
_fn_name = 'isEscapePossible'
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: 7986