Nesting - a920604a/leetcode GitHub Wiki
經典stack 教材
// you can use includes, for example:
// #include <algorithm>
// you can write to stdout for debugging purposes, e.g.
// cout << "this is a debug message" << endl;
#include<stack>
int solution(string &S) {
// write your code in C++14 (g++ 6.2.0)
stack<char> sta;
for(char c:S){
if(c=='(' || c=='[' || c=='{') sta.push(c);
else{
if(sta.empty()) return false;
else if(sta.top() == '(' && c==')') sta.pop();
else if(sta.top() == '[' && c==']') sta.pop();
else if(sta.top() == '{' && c=='}') sta.pop();
else return false;
}
}
return sta.empty();
}
- time complexity
O(n)
- space complexity
O(n)