LeetCode in Kotlin

205. Isomorphic Strings

Easy

Given two strings s and t, determine if they are isomorphic.

Two strings s and t are isomorphic if the characters in s can be replaced to get t.

All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character, but a character may map to itself.

Example 1:

Input: s = “egg”, t = “add”

Output: true

Example 2:

Input: s = “foo”, t = “bar”

Output: false

Example 3:

Input: s = “paper”, t = “title”

Output: true

Constraints:

• 1 <= s.length <= 5 * 104
• t.length == s.length
• s and t consist of any valid ascii character.

Solution

class Solution {
    fun isIsomorphic(s: String, t: String): Boolean {
        val map = IntArray(128)
        val str = s.toCharArray()
        val tar = t.toCharArray()
        val n = str.size
        for (i in 0 until n) {
            if (map[tar[i].code] == 0) {
                if (search(map, str[i].code, tar[i].code) != -1) {
                    return false
                }
                map[tar[i].code] = str[i].code
            } else {
                if (map[tar[i].code] != str[i].code) {
                    return false
                }
            }
        }
        return true
    }

    private fun search(map: IntArray, tar: Int, skip: Int): Int {
        for (i in 0..127) {
            if (i == skip) {
                continue
            }
            if (map[i] != 0 && map[i] == tar) {
                return i
            }
        }
        return -1
    }
}

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