LeetCode Valid Parentheses非常简单的解法

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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.

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非常简单，只需用栈实现即可。

bool isValid(string s) {
stack<char> st;
for(char c : s){
if(c == '('|| c == '{' || c == '['){
st.push(c);
}else{
if(st.empty()) return false;
if(c == ')' && st.top() != '(') return false;
if(c == '}' && st.top() != '{') return false;
if(c == ']' && st.top() != '[') return false;
st.pop();
}
}
return st.empty();
}