【leetcode】1002. Find Common Characters

class Solution {
    public List<String> commonChars(String[] A) {
        List<String> dups = new ArrayList();
        int length = A[0].length();
        for(int i=0; i<length; i++) {
            char c = A[0].charAt(i);
            for (int j=1; j<A.length; j++) {
                if (!A[j].contains(String.valueOf(c))) {
                    break;
                }
                A[j] = A[j].substring(0,A[j].indexOf(c)) + A[j].substring(A[j].indexOf(c)+1);
                if (j==A.length-1)
                    dups.add(String.valueOf(c));
            }
        }
        return dups;
    }
}