leetcode 20. Valid Parentheses
2016-03-17 19:50
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1.题目
Given a string containing just the characters
determine if the input string is valid.
The brackets must close in the correct order,
all valid but
not.
2.思路
检查字符串的括号是否使用正确,自然是用栈了。
lass Solution {
public:
bool isValid(string s) {
stack<char> tmp;
for(int i=0;i<s.size();i++)
{
if(tmp.empty()) tmp.push(s[i]);
else {
if(tmp.top()=='(' && s[i]==')') tmp.pop();
else if(tmp.top()=='[' && s[i]==']') tmp.pop();
else if(tmp.top()=='{' && s[i]=='}') tmp.pop();
else tmp.push(s[i]);
}
}
if(tmp.empty()) return 1;
else return 0;
}
};
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.
2.思路
检查字符串的括号是否使用正确,自然是用栈了。
lass Solution {
public:
bool isValid(string s) {
stack<char> tmp;
for(int i=0;i<s.size();i++)
{
if(tmp.empty()) tmp.push(s[i]);
else {
if(tmp.top()=='(' && s[i]==')') tmp.pop();
else if(tmp.top()=='[' && s[i]==']') tmp.pop();
else if(tmp.top()=='{' && s[i]=='}') tmp.pop();
else tmp.push(s[i]);
}
}
if(tmp.empty()) return 1;
else return 0;
}
};
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