Valid Parentheses 合法的括号匹配

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.

题目大意：给定一个字符串只包含“(){}[]”,判断该字符串的括号是否匹配

思路：利用栈的思想，不匹配入栈，匹配出栈，最后查看栈顶

#include <string.h>bool isValid(char* s) {    int len = strlen(s);    char *p = malloc(len);    int top = 0;    //从下标1开始存储        if(!p)        return false;    memset(p, 0x0, len);    while(*s)    {        //查看assic码，得知匹配情况的assic码差值        if(*s - p[top] == 1 || *s - p[top] == 2)        {            p[top] = 0;            top--;        }        else        {            top++;            p[top] = *s;        }        s++;    }    free(p);    return (top ? false : true);}