The idea of bracket matching algorithm

1) where the left bracket appears, the stack is entered;
2) Where the right parenthesis appears, first check if the stack is empty
If the stack is empty, it indicates that the "right parenthesis" is superfluous,
Otherwise, compared to the top element of the stack,
If matching, then "left bracket out of the stack",
Otherwise, the mismatch is indicated.
3) At the end of an expression test,
If the stack is empty, it indicates that the expression matches correctly,
Otherwise, "left bracket" is more than

There is a match:
Two variables left and right are added, and the number of parentheses is recorded, if not equal, the pairing is not completed.

The idea of bracket matching algorithm