LeetCode in Kotlin
2609. Find the Longest Balanced Substring of a Binary String
Easy
You are given a binary string s consisting only of zeroes and ones.
A substring of s is considered balanced if all zeroes are before ones and the number of zeroes is equal to the number of ones inside the substring. Notice that the empty substring is considered a balanced substring.
Return the length of the longest balanced substring of s.
A substring is a contiguous sequence of characters within a string.
Example 1:
Input: s = “01000111”
Output: 6
Explanation: The longest balanced substring is “000111”, which has length 6.
Example 2:
Input: s = “00111”
Output: 4
Explanation: The longest balanced substring is “0011”, which has length 4.
Example 3:
Input: s = “111”
Output: 0
Explanation: There is no balanced substring except the empty substring, so the answer is 0.
Constraints:
1 <= s.length <= 50'0' <= s[i] <= '1'
Solution
class Solution {
fun findTheLongestBalancedSubstring(s: String): Int {
val n = s.length
var max = 0
var countZeros = 0
var countOnes = 0
var temp = 0
for (i in 0 until n) {
if (s[i] == '0') {
countOnes = 0
countZeros++
}
if (s[i] == '1') {
countOnes++
temp = countZeros
if (i < n - 1 && s[i + 1] == '0') countZeros = 0
}
if (countOnes <= temp) max = max.coerceAtLeast(countOnes)
}
return 2 * max
}
}