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本文链接:https://blog.csdn.net/shiliang97/article/details/101993070
Given a string containing just the characters '('
, ')'
, '{'
, '}'
, '['
and ']'
, determine if the input string is valid.
An input string is valid if:
Note that an empty string is also considered valid.
Example 1:
Input: "()"
Output: true
Example 2:
Input: "()[]{}"
Output: true
Example 3:
Input: "(]"
Output: false
Example 4:
Input: "([)]"
Output: false
Example 5:
Input: "{[]}"
Output: true
class Solution {
public:
bool isValid(string s) {
stack<int> t;
for(int i=0;i<s.length();i++)
{
if(s[i]=='('||s[i]=='['||s[i]=='{'){
t.push(s[i]);
}else if(s[i]==')'){
if(i==0||t.empty()||t.top()!='('){
return false;
}
t.pop();
}else if(s[i]=='}'){
if(i==0||t.empty()||t.top()!='{'){
return false;
}
t.pop();
}else if(s[i]==']'){
if(i==0||t.empty()||t.top()!='['){
return false;
}
t.pop();
}
}
return t.empty();
}
};