【刷题·栈】20. 有效的括号

代码

/*
 * @lc app=leetcode.cn id=20 lang=cpp
 *
 * [20] 有效的括号
 */

#include
#include
using namespace std;

// @lc code=start
class Solution {
public:
    bool isValid(string s) {
        stack<char> sp;
        int size = s.size();
        for(int i=0; i<size; ++i)
        {
            if(s[i]=='(' || s[i]=='{' || s[i]=='[')
            {
                sp.push(s[i]);
            }
            else
            {
                if(sp.empty()==false)
                {
                    char topc = sp.top();
                    switch(s[i])
                    {
                        case ')':
                            if(topc == '(')
                            {
                                sp.pop();
                                break;
                            }
                            else 
                            {
                                return false;
                            }
                        case '}':
                            if(topc == '{')
                            {
                                sp.pop();
                                break;
                            }
                            else{
                                return false;
                            }
                        case ']':
                            if(topc == '[')
                            {
                                sp.pop();
                                break;
                            }
                            else{
                                return false;
                            }

                        default:
                            break;                         
                    }
                }
                else
                {
                    return false;
                }
            }
        }
        if(sp.empty() == false)
        {
            return false;
        }
        return true;
    }
};
// @lc code=end

结果

Accepted
96/96 cases passed (0 ms)
Your runtime beats 100 % of cpp submissions
Your memory usage beats 42.07 % of cpp submissions (6.6 MB)