LeetCode in Kotlin
830. Positions of Large Groups
Easy
In a string s of lowercase letters, these letters form consecutive groups of the same character.
For example, a string like s = "abbxxxxzyy" has the groups "a", "bb", "xxxx", "z", and "yy".
A group is identified by an interval [start, end], where start and end denote the start and end indices (inclusive) of the group. In the above example, "xxxx" has the interval [3,6].
A group is considered large if it has 3 or more characters.
Return the intervals of every large group sorted in increasing order by start index.
Example 1:
Input: s = “abbxxxxzzy”
Output: [[3,6]]
Explanation: "xxxx" is the only large group with start index 3 and end index 6.
Example 2:
Input: s = “abc”
Output: []
Explanation: We have groups “a”, “b”, and “c”, none of which are large groups.
Example 3:
Input: s = “abcdddeeeeaabbbcd”
Output: [[3,5],[6,9],[12,14]]
Explanation: The large groups are “ddd”, “eeee”, and “bbb”.
Constraints:
1 <= s.length <= 1000scontains lowercase English letters only.
Solution
class Solution {
fun largeGroupPositions(s: String): List<List<Int>> {
val map: MutableList<List<Int>> = ArrayList()
var i = 0
while (i < s.length) {
var j = i
while (j < s.length && s[j] == s[i]) {
j++
}
if (j - 1 - i + 1 >= 3) {
map.add(listOf(i, j - 1))
}
i = j
}
return map
}
}