Implement a function for determining the validity of a string. The string is valid if parentheses are correctly distributed within the string.

Question

Code Review · Accepted Answer

Most of your answers fail. You only count to make sure the number of left parentheses equals the number of right parentheses. You don't check if they are valid. Example ')()(' would pass your checks when it should fail.

PD_midday · Answer

Public Boolean check(string str) {
     Int  left_count = 0;
     Int right_count = 0;
     For(int x =0; x

Anonymous · Answer

def iterator(string):
    length = len(string)
    listOfIndices = []
    for i in range(length):
        if string[i] == '(':
            stillValid = findMatch(i, string, listOfIndices)
            if not stillValid:
                return False
    for i in range(length):
        if string[i] == ')':
            if i not in listOfIndices:
                return False
    return True


def findMatch(currIndex, string, listOfIndices):
    length = len(string)
    if currIndex == length -1:
        return False
    for i in range(currIndex+1,length):
        if i not in listOfIndices:
            if string[i]==')':
                listOfIndices.append(i)
                return True
    return False


def main():
    string = "(())("
    print iterator(string)
    string = "("
    print iterator(string)
    string = "hey)"
    print iterator(string)
    string = ")()()()("
    print iterator(string)
    string = "(()()(mnmn)00)" #should be valid
    print iterator(string)

Sam · Answer

public static boolean check(String s){
		int openParen = 0;
		for(int i = 0; i < s.length(); i++){
			if(s.charAt(i) == '('){
				openParen++;
			}
			if(s.charAt(i) == ')'){
				if(openParen == 0){
					return false;
				}
				openParen--;
			}
			
		}
		return openParen == 0;
	}

Jack · Answer

#include 
using namespace std;

int main() 
{
	
	int l=0;
	int r=0;
	string str = "";
    for(char& c : str) {
    if(c=='(') l++; 
	else if(c==')' && r!=l) r++; 
	else { cout << "invalid string" << endl; return 0; }
	}
	if(l==r)cout << "valid string" << endl;
}

raizel17 · Answer

#return true for valid, false for invalid
def validParens(string):

	length = len(string)
	left = 0
	right = 0

	for i in range(length):
		if string[i] == "(":
			left += 1

		elif string[i] == ")":
			right += 1

		if right > left:
			return False

	return True

Joe · Answer

public boolean isBalanced(String text) {
        int left = 0;
        int right = 0;

        for (int i = 0; i  left) {
                return false;
            }
        }
        return (left == right);
    }

Joe · Answer

public boolean isBalanced(String text) {
        int left = 0;
        int right = 0;

        for (int i = 0; i  left) {
                return false;
            }
        }
        return (left == right);
    }

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