LeetCode in Kotlin
1542. Find Longest Awesome Substring
Hard
You are given a string s. An awesome substring is a non-empty substring of s such that we can make any number of swaps in order to make it a palindrome.
Return the length of the maximum length awesome substring of s.
Example 1:
Input: s = “3242415”
Output: 5
Explanation: “24241” is the longest awesome substring, we can form the palindrome “24142” with some swaps.
Example 2:
Input: s = “12345678”
Output: 1
Example 3:
Input: s = “213123”
Output: 6
Explanation: “213123” is the longest awesome substring, we can form the palindrome “231132” with some swaps.
Constraints:
1 <= s.length <= 105sconsists only of digits.
Solution
class Solution {
fun longestAwesome(s: String): Int {
val n = s.length
val idx = IntArray(Math.pow(2.0, 10.0).toInt())
idx.fill(Int.MAX_VALUE)
idx[0] = -1
var mask = 0
var ans = 0
for (i in 0 until n) {
mask = mask xor (1 shl s[i].code - '0'.code)
ans = Math.max(ans, i - idx[mask])
for (j in 0..9) {
ans = Math.max(ans, i - idx[mask xor (1 shl j)])
}
idx[mask] = Math.min(idx[mask], i)
}
return ans
}
}