Brooke

一、題目

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.

 

二、程式作法

public class Solution
{
    public bool AreAlmostEqual(string s1, string s2)
    {
        if (s1 == s2) return true;
        for (int i = 0; i < s2.Length - 1; i++)
            for (int j = i + 1; j < s2.Length; j++)
            {
                char[] cs2 = s2.ToCharArray();
                char temp = cs2[i];
                cs2[i] = cs2[j];
                cs2[j] = temp;

                if (s1 == new string(cs2))
                    return true;
            }
        return false;
    }
}

 

三、思路筆記

題目要的是判斷兩字串是否其中一字元做一次字元交換後就等於對方字串。