leetcode/validParentheses.cpp at master · brianwu291/leetcode · GitHub

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#include <iostream>
#include <string>
#include <vector>

// https://leetcode.com/problems/valid-parentheses/

class Solution
{
public:
  bool isValid(std::string s)
  {
    int length = s.size();
    if (length == 1)
      return false;

    std::vector<std::string> openedStack;
    bool result = true;
    for (int i = 0; i < length && result; i += 1)
    {
      char curChar = s[i];
      std::string curStr;
      curStr.push_back(curChar);
      if (
          curStr == "{" || curStr == "[" || curStr == "(")
      {
        openedStack.push_back(curStr);
      }
      else if (openedStack.size() > 0)
      {
        std::string curOpenedStr = openedStack.back();
        openedStack.pop_back();
        if (curStr == "}" && curOpenedStr != "{")
          result = false;
        if (curStr == "]" && curOpenedStr != "[")
          result = false;
        if (curStr == ")" && curOpenedStr != "(")
          result = false;
      }
      else
      {
        return false;
      }
    }
    if (result == false)
      return false;
    return openedStack.empty();
  }
};