[问题描述]
Given a string containing just the characters ‘(‘, ‘)‘, ‘{‘, ‘}‘, ‘[‘ and ‘]‘, determine if the input string is valid.
The brackets must close in the correct order, "()" and "()[]{}" are all valid but "(]" and "([)]" are not.
[解题思路]
经典括号匹配问题，使用栈模拟即可
1 bool Solution::isValid(std::string s) 2 { 3 std::stack<char> tmp; 4 for (int i = 0; i < s.length(); i ++){ 5 if (s[i] == ‘(‘ || s[i] == ‘[‘ || s[i] == ‘{‘) 6 tmp.push(s[i]); 7 else if (s[i] == ‘)‘){ 8 if (tmp.size() > 0 && tmp.top() == ‘(‘) 9 tmp.pop(); 10 else 11 return false; 12 } 13 else if (s[i] == ‘]‘){ 14 if (tmp.size() > 0 && tmp.top() == ‘[‘) 15 tmp.pop(); 16 else 17 return false; 18 } 19 else if (s[i] == ‘}‘){ 20 if (tmp.size() > 0 && tmp.top() == ‘{‘) 21 tmp.pop(); 22 else 23 return false; 24 } 25 } 26 return tmp.size() == 0; 27 }
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原文：http://www.cnblogs.com/taizy/p/3911276.html