Uber: One Edit Distance

public boolean isOneEditDistance(String s, String t) {
int m = s.length(), n = t.length();
if (m > n) return isOneEditDistance(t, s);
if (n - m > 1) return false;
int i = 0, shift = n - m;
while (i < m && s.charAt(i) == t.charAt(i)) i++;
if (i == m) return shift > 0;
if (shift == 0) i++;
while (i < m && s.charAt(i) == t.charAt(i + shift)) i++;
return i == m;
}