LeetCode之Partition Labels（Kotlin）

問題： A string S of lowercase letters is given. We want to partition this string into as many parts as possible so that each letter appears in at most one part, and return a list of integers representing the size of these parts.

Example 1:
Input: S = "ababcbacadefegdehijhklij"
Output: [9,7,8]
Explanation:
The partition is "ababcbaca", "defegde", "hijhklij".
This is a partition so that each letter appears in at most one part.
A partition like "ababcbacadefegde", "hijhklij" is incorrect, because it splits S into less parts.
複製代碼

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方法： 向右遍歷，當index與index所處位置字符的最右index相同時分組，當遍歷完全部字符後輸出即爲結果。（我也知道不太好理解，看代碼慢慢體會o(╯□╰)o）

具體實現：

class PartitionLabels {
    fun partitionLabels(S: String): List<Int> {
        val result = mutableListOf<Int>()

        val last = IntArray(26)

        for (i in S.indices) {
            last[S[i] - 'a'] = i
        }

        var j = 0
        var anchor = 0
        for (i in S.indices) {
            j = maxOf(j, last[S[i] - 'a'])
            if (i == j) {
                result.add(i - anchor + 1)
                anchor = i + 1
            }
        }

        return result
    }
}

fun main(args: Array<String>) {
    val partitionLabels = PartitionLabels()
    var string = "ababcbacadefegdehijhklij"
    println(partitionLabels.partitionLabels(string))
}
複製代碼

有問題隨時溝通

具體代碼實現能夠參考Github