1790. Check if One String Swap Can Make Strings Equal

Problem

You are given two strings s1 and s2 of equal length. A string swap is an operation where you choose two indices in a string (not necessarily different) and swap the characters at these indices.

Return true **if it is possible to make both strings equal by performing **at most one string swap **on *exactly one* of the strings. **Otherwise, return false.

  Example 1:

Input: s1 = "bank", s2 = "kanb"
Output: true
Explanation: For example, swap the first character with the last character of s2 to make "bank".

Example 2:

Input: s1 = "attack", s2 = "defend"
Output: false
Explanation: It is impossible to make them equal with one string swap.

Example 3:

Input: s1 = "kelb", s2 = "kelb"
Output: true
Explanation: The two strings are already equal, so no string swap operation is required.

  Constraints:

• 1 <= s1.length, s2.length <= 100

• s1.length == s2.length

• s1 and s2 consist of only lowercase English letters.

Solution

/**
 * @param {string} s1
 * @param {string} s2
 * @return {boolean}
 */
var areAlmostEqual = function(s1, s2) {
    var diffs = [];
    for (var i = 0; i < s1.length; i++) {
        if (s1[i] !== s2[i]) diffs.push(i);
    }
    return diffs.length === 0 || (
        diffs.length === 2 &&
            s1[diffs[0]] === s2[diffs[1]] &&
            s1[diffs[1]] === s2[diffs[0]]
    );
};

Explain:

nope.

Complexity:

• Time complexity : O(n).
• Space complexity : O(n).