Note:

1. Need check i < s.length() and j < t.length(). 

2. Only make i-- when s.length() < t.length() since it could be replacement. No need for shift

class Solution {    public boolean isOneEditDistance(String s, String t) {        if (s.length() > t.length()) {            return isOneEditDistance(t, s);        }                if (t.length() - s.length() > 1) {            return false;        }                boolean found = false;        for (int i = 0, j = 0; i < s.length() && j < t.length(); i++, j++) {            if (s.charAt(i) != t.charAt(j)) {                if (found) {                    return false;                }                found = true;                if (t.length() > s.length()) {                    i--;                }            }        }        return found || (t.length() - s.length()) == 1;    }}