Length of the longest valid substring
/*
http://ideone.com/rdL7A2
http://www.geeksforgeeks.org/length-of-the-longest-valid-substring/
http://www.practice.geeksforgeeks.org/problem-page.php?pid=960
*/
#include<bits/stdc++.h>
using namespace std;
int validSubString(string str){
int len = str.size();
stack<char> s;
s.push(-1);
int count = 0;
for(int i=0; i<len; i++){
if(str[i] == '(')
s.push(i);
else{
s.pop();
if(!s.empty()){
count = max(count, i - s.top());
}else{
s.push(i);
}
}
}
return count;
}
int main() {
int t;
cin >> t;
while(t--){
string s;
cin >> s;
cout << validSubString(s) <<endl;
}
return 0;
}