Valid Parentheses

Link

Just used the stack data structure and popped something out when a closing symbol appeared. If I didn't get what was expected, I returned false.

Full Solution in Java:

 public class Solution {
    public boolean isValid(String s) {
        Stack< Character> st = new Stack< Character>();
        
        for(int i=0; i< s.length(); i++){
            
            char x= s.charAt(i);
            
            if(x==')'){
                if(st.empty()){
                    return false;
                }
                char c = st.pop();
                if(c!='('){
                    return false;
                }
            }
            else if(s.charAt(i)=='}'){
                if(st.empty()){
                    return false;
                }
                char c = st.pop();
                if(c!='{'){
                    return false;
                }
            }
            
            else if(s.charAt(i)==']'){
                if(st.empty()){
                    return false;
                }
                char c = st.pop();
                if(c!='['){
                    return false;
                }
            }
            
            
            else{
                st.push(s.charAt(i));
            }
        }
        
        if(!st.empty()){
            return false;
        }
        
        return true;
    }
}