LeetCode之Insert Interval（Kotlin）

最新推荐文章于 2024-06-11 09:45:11 发布

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原文链接：https://juejin.im/post/5c9a1d1fe51d454e2b272eab

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#移动开发 #数据结构与算法

本文介绍了一种插入区间并合并重叠区间的算法实现。该算法首先将新的区间插入到已排序的区间列表中，并通过遍历判断每个原有区间与新区间的位置关系来合并重叠区间，最终返回更新后的区间列表。

问题： Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary). You may assume that the intervals were initially sorted according to their start times.

Example 1:

Input: intervals = [[1,3],[6,9]], newInterval = [2,5]
Output: [[1,5],[6,9]]
Example 2:

Input: intervals = [[1,2],[3,5],[6,7],[8,10],[12,16]], newInterval = [4,8]
Output: [[1,2],[3,10],[12,16]]
Explanation: Because the new interval [4,8] overlaps with [3,5],[6,7],[8,10].
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方法：先创建结果list，然后添加newInterval作为基准，然后遍历intervals所有元素，区间在newInterval左边的区间add到左边，区间在newInterval右边的区间add到右边，如果区间有交叠则与newInterval做合并，最后遍历结束即为结果。

具体实现：

class InsertInterval {
    // Definition for an interval.
    class Interval(var start: Int = 0, var end: Int = 0) {
        override fun toString(): String {
            return "Interval(start=$start, end=$end)"
        }
    }

    fun insert(intervals: List<Interval>, newInterval: Interval): List<Interval> {
        val result = mutableListOf<Interval>()
        result.add(newInterval)
        for (interval in intervals) {
            if (interval.end < newInterval.start) {
                result.add(result.lastIndex, interval)
            } else if (interval.start > newInterval.end) {
                result.add(result.lastIndex+1, interval)
            } else if (interval.start <= newInterval.start && interval.end >= newInterval.end ) {
                newInterval.start = interval.start
                newInterval.end = interval.end
            } else if (interval.start <= newInterval.start && interval.end < newInterval.end) {
                newInterval.start = interval.start
            } else if (interval.start > newInterval.start && interval.end >= newInterval.end) {
                newInterval.end = interval.end
            }
        }
        return result
    }
}

fun main(args: Array<String>) {
    val intervals = listOf(InsertInterval.Interval(2, 6), InsertInterval.Interval(7, 9))
    val newInterval = InsertInterval.Interval(15, 18)
    val insertInterval = InsertInterval()
    for (ele in insertInterval.insert(intervals, newInterval)) {
        println(ele)
    }
}
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