description:

check whether the (){}[] is valid(is pair)

Note:

Example:

Example 1:Input: "()"Output: trueExample 2:Input: "()[]{}"Output: trueExample 3:Input: "(]"Output: falseExample 4:Input: "([)]"Output: falseExample 5:Input: "{[]}"Output: true

my answer:

my answer

一眼想到堆栈，奈何堆栈没有想起我，堆栈的用法get一下ok吧...

大佬的answer：

class Solution {public:    bool isValid(string s) {        stack
    
      res;        for(int i = 0; i < s.size(); ++i){            if(s[i] == '(' || s[i] == '[' || s[i] == '{') res.push(s[i]);            else{                if(res.empty()) return false;                if(s[i] == ')' && res.top() != '(')return false;                if(s[i] == ']' && res.top() != '[')return false;                if(s[i] == '}' && res.top() != '{')return false;                res.pop();            }        }        return res.empty();    }};
    

relative point get√：

stackres; //definite a stack

stack.top(); // the element on the top of the stack

stack.push(xxx); // push a element on the top of the stack

stack.pop(); // pop the element on the top of the stack

stack.empty();

hint :