[刷题] LeetCode 20.Valid Parentheses

字符串匹配

 1 #include<iostream>
 2 #include<stack>
 3 #include<cassert>
 4 
 5 using namespace std;
 6 
 7 class Solution{
 8     public:
 9         bool isValid(string s){
10             
11             stack<char> stack;
12             for( int i = 0 ; i < s.size() ; i ++ ){
13                 if( s[i] == '(' || s[i] == '{' || s[i] == '[')
14                     stack.push( s[i] );
15                 else{
16                     
17                     if( stack.size() == 0) 
18                         return false;
19                         
20                     char c = stack.top();
21                     stack.pop();
22                     
23                     char match;
24                     if( s[i] == ')')
25                         match = '(';
26                     else if( s[i] == ']' )
27                         match = '[';
28                     else{
29                         assert( s[i] == '}' );
30                         match = '{';
31                     }
32                     
33                     if( c != match)
34                         return false;
35                 }
36             }
37             
38             if( stack.size() != 0 )
39                 return false;
40                 
41             return true;    
42         }
43 };
44 
45 void printBool(bool res){
46     cout << (res ? "True" : "False") << endl;
47 }
48 
49 int main(){
50     
51     printBool(Solution().isValid("()"));
52     printBool(Solution().isValid("()[]{}"));
53     printBool(Solution().isValid("(]"));
54     printBool(Solution().isValid("([)]"));
55     
56     return 0;
57 }