将字符串转换成数字，再进行比较

class Solution {
    
    
    public boolean isSumEqual(String firstWord, String secondWord, String targetWord) {
    
    
        String first = new String();
        String second = new String();
        String target = new String();
        for(int i=0;i<firstWord.length();i++){
    
    
            first +=(firstWord.charAt(i)-'a');
        }
        for(int i=0;i<secondWord.length();i++){
    
    
           second += (secondWord.charAt(i) - 'a');
        }
        for(int i=0;i<targetWord.length();i++){
    
    
            target +=(targetWord.charAt(i)-'a');
        }
        int a=Integer.valueOf(first);
         int b=Integer.valueOf(second);
          int c=Integer.valueOf(target);
          if(a+b==c){
    
    
              return true;
          }
          return false;
    }
}