LeetCode之Find Smallest Letter Greater Than Target（Kotlin）

问题： Given a list of sorted characters letters containing only lowercase letters, and given a target letter target, find the smallest element in the list that is larger than the given target. Letters also wrap around. For example, if the target is target = 'z' and letters = ['a', 'b'], the answer is 'a'.

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方法： 两种状况：第一种target大于全部元素，则result应该返回全部元素的最小值；第二种状况target在'a'和'z'之间，则返回大于target的最小值。

具体实现：

class NextGreatestLetter {
    fun nextGreatestLetter(letters: CharArray, target: Char): Char {
        var result = 'z'
        var min = letters[0]
        var wrapAround = true
        for(ch in letters) {
            if (ch > target && ch <= result) {
                result = ch
                wrapAround = false
            }
            if (ch < min) {
                min = ch
            }
        }
        if (wrapAround) {
            return min
        }
        return result
    }
}

fun main(args: Array<String>) {
    val array = charArrayOf('c', 'f', 'j')
    val target = 'c'
    val nextGreatestLetter = NextGreatestLetter()
    val result = nextGreatestLetter.nextGreatestLetter(array, target)
    println("result: $result")
}
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具体代码实现能够参考Github