161-one-edit-distance.js

/**

Given two strings s and t, determine if they are both one edit distance apart.

Note: 

There are 3 possiblities to satisify one edit distance apart:

Insert a character into s to get t
Delete a character from s to get t
Replace a character of s to get t
Example 1:

Input: s = "ab", t = "acb"
Output: true
Explanation: We can insert 'c' into s to get t.
Example 2:

Input: s = "cab", t = "ad"
Output: false
Explanation: We cannot get t from s by only one step.
Example 3:

Input: s = "1203", t = "1213"
Output: true
Explanation: We can replace '0' with '1' to get t.

*/

/**
 * @param {string} s
 * @param {string} t
 * @return {boolean}
 */
const isOneEditDistance = function(s, t) {
  const m = s.length,
    n = t.length;
  if (m > n) {
    return isOneEditDistance(t, s);
  }
  for (let i = 0; i < m; i++) {
    if (s[i] !== t[i]) {
      if (m === n) {
        return s.slice(i + 1) === t.slice(i + 1);
      }
      return s.slice(i) === t.slice(i + 1);
    }
  }
  return m + 1 === n;
};