Given two strings S and T, determine if they are both one edit distance apart

题目：

Given two strings S and T, determine if they are both one edit distance apart

i. Modify operation – Modify a character to X in S.
S = “abcde”
T = “abXde”

ii. Insert operation – X was inserted before a character in S.
S = “abcde”
T = “abcXde”

iii. Append operation – X was appended at the end of S.
S = “abcde”
T = “abcdeX”

解答：

public class Solution {

    public static void main(String[] args) {
        String s = "abcde";
        String t = "abcdeX";

        System.out.println(isOneEditDistance(s, t));
    }

    public boolean isOneEditDistance(String s, String t) {
        int m = s.length();
        int n = t.length();
        if(m > n) {
            return isOneEditDistance(t, s);
        }

        if(n - m > 1) {
            return flase;
        }

        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;
    }

}