Read from standard input a string of at most 2000 characters that may contain round brackets ( ), square brackets [ ], curly braces { }, and any other characters (letters, digits, operators).
We say the string has balanced brackets if:
- every opening bracket has a matching closing bracket of the same type;
- brackets close in the reverse order of opening (they do not intersect).
Print DA if the brackets are balanced and NU otherwise.
Use a stack implemented with a character array and an index top. Do not use STL containers.