Implement get(object, path) for nested Map/Array access

Implement get(obj, path) to retrieve a value from a nested object made of arbitrary combinations of Maps (objects) and Arrays (lists), using a path string. Path grammar: . accesses a map key. [...] accesses an array index (non-negative integer). They can be chained, e.g. ab[1].c.d[2][13]. Input: Line 1: a JSON value (objects/arrays/numbers/strings/bools/null). Line 2: the path string. Output: Print the target value as JSON if it exists and the path is valid. Otherwise print null. Constraints: Total nodes/elements N: 1 <= N <= 2e5 Path length L: 1 <= L <= 2e5 Aim for ~O(L) path parsing and iterative traversal. Task: Parse the path and walk the structure step-by-step. Example Input {"ab":[{"c":1},{"c":{"d":[0,1,[10,11,[100]]]} } ]} ab[1].c.d[2][2][0] Output 100