47 lines
927 B
C++
47 lines
927 B
C++
#include <stack>
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#include <string>
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/**
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* 20. Valid Parentheses
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*
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* Given a string s containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.
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*
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* An input string is valid if:
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*
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* Open brackets must be closed by the same type of brackets.
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* Open brackets must be closed in the correct order.
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* Every close bracket has a corresponding open bracket of the same type.
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*/
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class Solution {
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public:
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static bool isValid(const std::string&);
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};
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bool Solution::isValid(const std::string& s) {
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std::stack<char> sc;
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for (char ch : s) {
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switch (ch) {
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case '[':
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case '(':
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case '{':
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sc.push(ch);
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break;
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case ']':
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case ')':
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case '}':
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if (sc.empty() || sc.top() != (ch ^ (ch < 64 ? 1 : 6)))
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return false;
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sc.pop();
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break;
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default:
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return false;
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}
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}
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return sc.empty();
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}
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int main() {
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Solution::isValid("()[]{}");
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return 0;
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} |