README_EN.md

1614. Maximum Nesting Depth of the Parentheses

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Description

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 1:

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

Example 2:

Input: s = "(1)+((2))+(((3)))"
Output: 3

Example 3:

Input: s = "1+(2*3)/(2-1)"
Output: 1

Example 4:

Input: s = "1"
Output: 0

 

Constraints:

• 1 <= s.length <= 100
• s consists of digits 0-9 and characters '+', '-', '*', '/', '(', and ')'.
• It is guaranteed that parentheses expression s is a VPS.

Solutions

Python3

class Solution:
    def maxDepth(self, s: str) -> int:
        res = depth = 0
        for c in s:
            if c == '(':
                depth += 1
                res = max(res, depth)
            elif c == ')':
                depth -= 1
        return res

Java

class Solution {
    public int maxDepth(String s) {
        int res = 0, depth = 0;
        for (char c : s.toCharArray()) {
            if (c == '(') {
                res = Math.max(res, ++depth);
            } else if (c == ')') {
                --depth;
            }
        }
        return res;
    }
}

C++

class Solution {
public:
    int maxDepth(string s) {
        int res = 0, depth =0;
        for (char c : s)
        {
            if (c == '(') res = max(res, ++depth);
            else if (c == ')') --depth;
        }
        return res;
    }
};

Go

func maxDepth(s string) int {
	res, depth := 0, 0
	for _, c := range s {
		if c == '(' {
			depth++
			if depth > res {
				res = depth
			}
		} else if c == ')' {
			depth--
		}
	}
	return res
}

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