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

public class Solution {

public boolean isOneEditDistance(String s, String t) {

int m = s.length(), n = t.length();

if(m == n) return isOneModified(s, t);

if(m - n == 1) return isOneDeleted(s, t);

if(n - m == 1) return isOneDeleted(t, s);

// 长度差距大于2直接返回false

return false;

}

private boolean isOneModified(String s, String t){

boolean modified = false;

// 看是否只修改了一个字符

for(int i = 0; i < s.length(); i++){

if(s.charAt(i) != t.charAt(i)){

if(modified) return false;

modified = true;

}

}

return modified;

}

public boolean isOneDeleted(String longer, String shorter){

// 找到第一组不一样的字符，看后面是否一样

for(int i = 0; i < shorter.length(); i++){

if(longer.charAt(i) != shorter.charAt(i)){

return longer.substring(i + 1).equals(shorter.substring(i));

}

}

return true;

}

}