問題: 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: 先建立結果list,然後新增newInterval作為基準,然後遍歷intervals所有元素,區間在newInterval左邊的區間add到左邊,區間在newInterval右邊的區間add到右邊,如果區間有交疊則與newInterval做合併,最後遍歷結束即為結果。
具體實現:
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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