LeetCode in Kotlin
1790. Check if One String Swap Can Make Strings Equal
Easy
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 <= 100s1.length == s2.lengths1ands2consist of only lowercase English letters.
Solution
class Solution {
fun areAlmostEqual(s1: String, s2: String): Boolean {
var i1 = -1
var i2 = -1
// We go though the two strings
for (i in 0 until s1.length) {
// check if each char is the same.
if (s1[i] == s2[i]) {
continue
}
// When there are more than 2 char different., we return false;
if (i2 != -1) {
return false
}
// If there is char that is different, we record the index.
if (i1 == -1) {
i1 = i
} else {
// If there is char that is different, we record the index.
i2 = i
}
}
// When three is no different char, we return true;
if (i1 == i2) {
return true
}
// When there is 1 char different, we return false;
return if (i2 == -1) {
false
} else s1[i1] == s2[i2] && s1[i2] == s2[i1]
// When there are 2 char different, and swap them can make two string equal, we return true;
}
}