#define MaxSize 10000  //定义栈中最大元素个数
typedef struct{  char data[MaxSize];  //ElemType元素类型，例如int  int top;  //定义栈顶指针}SqStack;
//初始化栈void InitStack(SqStack &S){    S.top = -1;  //从-1开始是因为S.top指向元素下标，当第一个元素进来，top+1正好对应下标0}
//新元素入栈bool push(SqStack &S, char x){  if(S.top == MaxSize - 1){ //栈满    return false;  }else{    S.top = S.top + 1;  //指针+1    S.data[S.top] = x;  //新元素入栈    return true;  }}
//栈的判空bool StackEmpty(SqStack S){  if (S.top == -1){    return true;  //栈空  }else{    return false;  //不空  }}
//出栈bool Pop(SqStack &S, char &x){  if(S.top == - 1){ //空栈    return false;  }else{    x = S.data[S.top];  //获取要出栈的元素    S.top = S.top - 1;  //指针-1    return true;  }}
class Solution {public:    bool isValid(string s) {        SqStack S;        InitStack(S);        int len = s.size();        for(int i=0; i<len; i++){            if(s[i]=='(' || s[i]=='[' || s[i]=='{'){                push(S, s[i]);            }else{                if (StackEmpty(S))                return false;                char topElem;                Pop(S, topElem);                if (s[i] == ')' && topElem != '(')                    return false;                if (s[i] == ']' && topElem != '[')                    return false;                                    if (s[i] == '}' && topElem != '{')                    return false;               }            }        return StackEmpty(S);    }};