Valid Parentheses
Given a string s containing just the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[’ and ‘]’, determine if the input string is valid.
An input string is valid if:
Open brackets must be closed by the same type of brackets. Open brackets must be closed in the correct order. Every close bracket has a corresponding open bracket of the same type.
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Example 1:
Input: s = "()"
Output: true
Example 2:
Input: s = "()[]{}"
Output: true
Example 3:
Input: s = "(]"
Output: false
C++ solution
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bool isValid(string s){
stack<char> parentheses;
for (auto character : s) {
switch(character){
case '(' :
case '[' :
case '{' :
parentheses.push(character);
break;
case ')':
if (parentheses.empty() || parentheses.top() != '(') {
return false;
}
if (!parentheses.empty()) {
parentheses.pop();
}
break;
case ']':
if (parentheses.empty() || parentheses.top() != '[') {
return false;
}
if (!parentheses.empty()) {
parentheses.pop();
}
break;
case '}':
if (parentheses.empty() || parentheses.top() != '{') {
return false;
}
if (!parentheses.empty()) {
parentheses.pop();
}
break;
}
}
return parentheses.empty();
}
