leetcode-cpp/0020-valid-parentheses.cpp at main · j414j/leetcode-cpp · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
#include <string>
#include <vector>
#include <iostream>
using namespace std;

class Solution
{
public:
    bool isValid(string s)
    {
        vector<char> stack;
        bool flag = false;
        for (int i = 0; i < s.length(); i++)
        {
            switch (s[i])
            {
            case '{':
                stack.push_back('{');
                break;
            case '(':
                stack.push_back('(');
                break;
            case '[':
                stack.push_back('[');
                break;

            case '}':
                if (stack.size() >= 1 && stack[stack.size() - 1] == '{')
                {
                    stack.pop_back();
                }
                else
                {
                    flag = true;
                }
                break;

            case ')':
                if (stack.size() >= 1 && stack[stack.size() - 1] == '(')
                {
                    stack.pop_back();
                }
                else
                {
                    flag = true;
                }
                break;

            case ']':
                if (stack.size() >= 1 && stack[stack.size() - 1] == '[')
                {
                    stack.pop_back();
                }
                else
                {
                    flag = true;
                }
                break;
            }
            if (flag)
            {
                break;
            }
        }

        if (flag || stack.size() != 0)
        {
            return false;
        }
        return true;
    }
};

int main()
{
    bool isValid = (new Solution())->isValid("[](){}");
}