020 - Valid Parentheses

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.

检查括号是否能匹配

一帮是用栈实现比较简单

bool isValid(char* s)
{
char stack[2048] = {0};
int sp = -1;
while (*s) {
if (*s == '{' || *s == '[' || *s == '(')
stack[++sp] = *s;
else if (*s == ')') {
if (stack[sp] == '(') sp--;
else break;
} else if (*s == ']') {
if (stack[sp] == '[') sp--;
else break;
} else if (*s == '}') {
if (stack[sp] == '{') sp--;
else break;
} else break;
s++;
}
return !*s && sp == -1? 1 : 0;
}