[Swift Weekly Contest 122]LeetCode986. 区间列表的交集 | Interval List Intersections

Given two lists of closed intervals,each list of intervals is pairwise disjoint and in sorted order.

Return the intersection of these two interval lists.

(Formally,a closed interval [a,b] (with a <= b) denotes the set of real numbers x with a <= x <= b.  The intersection of two closed intervals is a set of real numbers that is either empty,or can be represented as a closed interval.  For example,the intersection of [1,3] and [2,4] is [2,3].)

Example 1:

Input: A = [[0,2],[5,10],[13,23],[24,25]],B = [[1,5],[8,12],[15,24],[25,26]] Output: [[1,25]] Reminder: The inputs and the desired output are lists of Interval objects,and not arrays or lists.

Note:

1. 0 <= A.length < 1000
2. 0 <= B.length < 1000
3. 0 <= A[i].start,A[i].end,B[i].start,B[i].end < 10^9

给定两个由一些闭区间组成的列表，每个区间列表都是成对不相交的，并且已经排序。

返回这两个区间列表的交集。

（形式上，闭区间 [a,b]（其中 a <= b）表示实数 x 的集合，而 a <= x <= b。两个闭区间的交集是一组实数，要么为空集，要么为闭区间。例如，[1,3] 和 [2,4] 的交集为 [2,3]。）

示例：

输入：A = [[0,B = [[1,26]]
输出：[[1,25]]
注意：输入和所需的输出都是区间对象组成的列表，而不是数组或列表。

提示：

1. 0 <= A.length < 1000
2. 0 <= B.length < 1000
3. 0 <= A[i].start,B[i].end < 10^9

1472 ms

 1 /**
 2  * DeFinition for an interval.
 3  * public class Interval {
 4  *   public var start: Int
 5  *   public var end: Int
 6  *   public init(_ start: Int,_ end: Int) {
 7  *     self.start = start
 8  *     self.end = end
 9  *   }
10  * }
11  */
12 class Solution {
13     func intervalIntersection(_ A: [Interval],_ B: [Interval]) -> [Interval] {
14         if A.isEmpty || B.isEmpty {return []}
15         var C:[Interval] = [Interval](repeating:Interval(0,1),count:A.count*B.count)
16         var p:Int = 0
17         for x in A
18         {
19             for y in B
20             {
21                 var l:Int = max(x.start,y.start)
22                 var r:Int = min(x.end,y.end)
23                 if l <= r
24                 {
25                     C[p] = Interval(l,r)
26                     p += 1
27                 }
28             }
29         }
30         if (p - 1) < C.count
31         {
32             var arr = C[0...(p - 1)]
33             return [Interval](arr)
34         }
35         return C
36     }
37 }