力扣（LeetCode）试题20-有效的括号 C++代码

 1 #include <iostream>
 2 #include <string>
 3 
 4 using namespace std;
 5 
 6 class Solution 
 7 {
 8 public:
 9     bool isValid(string s) 
10     {
11         bool flag;
12         if (s.length() % 2 != 0)
13             flag = 0;
14         if (s.length() == 0)
15             flag = 1;
16         else
17         {
18             int s_m = s.length() / 2;
19             int k = s.length();
20             for (int i = 0; i < s_m; i++)
21             {
22                 k -= 1;
23                 if ((s[i] == ‘(‘ && s[k] == ‘)‘) || ((s[i] == ‘[‘ && s[k] == ‘]‘))
24                     || ((s[i] == ‘{‘ && s[k] == ‘}‘)))
25                 {
26                     flag = 1;                
27                 }
28                 else 
29                 {
30                     for (int j = 0; j < s.length(); j = j + 2)
31                     {
32                         if ((s[j] == ‘(‘ && s[j + 1] == ‘)‘) || ((s[j] == ‘[‘ && s[j + 1] == ‘]‘))
33                             || ((s[j] == ‘{‘ && s[j + 1] == ‘}‘)))
34                             flag = 1;
35                         else
36                             flag = 0;
37                     }
38                 }
39             
40             }
41         }
42         return flag;
43     }
44 };
45 
46 int main(){
47     bool result;
48     Solution sol;
49     string str = "{[]}";
50     result = sol.isValid(str);
51     cout << result << endl;
52     int y;
53     cin >> y;
54     return 0;
55 }