class Solution {
    
    private Map charMap=new HashMap();
    public boolean isValid(String s) {
        
        //1.
        //2. 
        //3.    
        //  3.1   
        //  3.2   
        //4. 0 0true false
        //   
        //3.
        if(s==null){
            return false;
        }
        if("".equals(s)){
            return true;
        }
        initMap(charMap);
     
        Stack stack=new Stack();
        char stackTopStr;
        char str;
        for(int i=0;i