Leetcode 1614 - Maximum Nesting Depth of the Parentheses

Note:

  • Don’t use stack and make it too complicate.

Question:

A string is a valid parentheses string (denoted VPS) if it meets one of the following:

  • It is an empty string "", or a single character not equal to "(" or “)”,
  • It can be written as AB (A concatenated with B), where A and B are VPS’s, or
  • It can be written as (A), where A is a VPS.

We can similarly define the nesting depth depth(S) of any VPS S as follows:

  • depth(“”) = 0
  • depth(C) = 0, where C is a string with a single character not equal to “(“ or “)”.
  • depth(A + B) = max(depth(A), depth(B)), where A and B are VPS’s.
  • depth(“(“ + A + “)”) = 1 + depth(A), where A is a VPS.

For example, “”, “()()”, and “()(()())” are VPS’s (with nesting depths 0, 1, and 2), and “)(“ and “(()” are not VPS’s.

Given a VPS represented as string s, return the nesting depth of s.

Example:

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Input: s = "(1+(2*3)+((8)/4))+1"
Output: 3
Explanation: Digit 8 is inside of 3 nested parentheses in the string.

Code:

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/**
* @param {string} s
* @return {number}
*/
var maxDepth = function(s) {
let ans = 0;
let cur = 0;
for (let i = 0; i < s.length; i++) {
if (s[i] === '(') cur++;
if (s[i] === ')') cur--;
if (cur > ans) ans = cur;
}
return ans;
};