网站内容好,网站开发猪八戒,代码编辑器,上海营销活动策划公司★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★➤微信公众号#xff1a;山青咏芝#xff08;shanqingyongzhi#xff09;➤博客园地址#xff1a;山青咏芝#xff08;https://www.cnblogs.com/strengthen/#xff09;➤GitHub地址山青咏芝shanqingyongzhi➤博客园地址山青咏芝https://www.cnblogs.com/strengthen/➤GitHub地址https://github.com/strengthen/LeetCode➤原文地址https://www.cnblogs.com/strengthen/p/11297779.html ➤如果链接不是山青咏芝的博客园地址则可能是爬取作者的文章。➤原文已修改更新强烈建议点击原文地址阅读支持作者支持原创★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★★ Implement a SnapshotArray that supports the following interface: SnapshotArray(int length) initializes an array-like data structure with the given length. Initially, each element equals 0.void set(index, val) sets the element at the given index to be equal to val.int snap() takes a snapshot of the array and returns the snap_id: the total number of times we called snap() minus 1.int get(index, snap_id) returns the value at the given index, at the time we took the snapshot with the given snap_idExample 1: Input: [SnapshotArray,set,snap,set,get]
[[3],[0,5],[],[0,6],[0,0]]
Output: [null,null,0,null,5]
Explanation:
SnapshotArray snapshotArr new SnapshotArray(3); // set the length to be 3
snapshotArr.set(0,5); // Set array[0] 5
snapshotArr.snap(); // Take a snapshot, return snap_id 0
snapshotArr.set(0,6);
snapshotArr.get(0,0); // Get the value of array[0] with snap_id 0, return 5 Constraints: 1 length 50000At most 50000 calls will be made to set, snap, and get.0 index length0 snap_id (the total number of times we call snap())0 val 10^9实现支持下列接口的「快照数组」- SnapshotArray SnapshotArray(int length) - 初始化一个与指定长度相等的 类数组 的数据结构。初始时每个元素都等于 0。void set(index, val) - 会将指定索引 index 处的元素设置为 val。int snap() - 获取该数组的快照并返回快照的编号 snap_id快照号是调用 snap() 的总次数减去 1。int get(index, snap_id) - 根据指定的 snap_id 选择快照并返回该快照指定索引 index 的值。示例 输入[SnapshotArray,set,snap,set,get][[3],[0,5],[],[0,6],[0,0]]
输出[null,null,0,null,5]
解释
SnapshotArray snapshotArr new SnapshotArray(3); // 初始化一个长度为 3 的快照数组
snapshotArr.set(0,5); // 令 array[0] 5
snapshotArr.snap(); // 获取快照返回 snap_id 0
snapshotArr.set(0,6);
snapshotArr.get(0,0); // 获取 snap_id 0 的快照中 array[0] 的值返回 5 提示 1 length 50000题目最多进行50000 次setsnap和 get的调用 。0 index length0 snap_id 我们调用 snap() 的总次数0 val 10^9480ms 1 class SnapshotArray {2 3 private var dict [Int: Int]()4 private var snapshots [[Int: Int]]()5 6 init(_ length: Int) {7 //array Array(repeating: 0, count: length 1)8 }9
10 func set(_ index: Int, _ val: Int) {
11 dict[index] val
12 }
13
14 func snap() - Int {
15 snapshots.append(dict)
16 return snapshots.count - 1
17 }
18
19 func get(_ index: Int, _ snap_id: Int) - Int {
20 return snapshots[snap_id][index] ?? 0
21 }
22 }
23
24 /**
25 * Your SnapshotArray object will be instantiated and called as such:
26 * let obj SnapshotArray(length)
27 * obj.set(index, val)
28 * let ret_2: Int obj.snap()
29 * let ret_3: Int obj.get(index, snap_id)
30 */ Runtime: 828 ms Memory Usage: 27.8 MB 1 class SnapshotArray {2 var vv:[[Int:Int]] [[Int:Int]]()3 4 init(_ length: Int) {5 vv.append([Int:Int]()) 6 }7 8 func set(_ index: Int, _ val: Int) {9 vv[vv.count - 1][index] val
10 }
11
12 func snap() - Int {
13 vv.append([Int:Int]())
14 return vv.count - 2
15 }
16
17 func get(_ index: Int, _ snap_id: Int) - Int {
18 for i in stride(from:snap_id,through:0,by:-1)
19 {
20 if vv[i][index] ! nil
21 {
22 return vv[i][index]!
23 }
24 }
25 return 0
26 }
27 }
28
29 /**
30 * Your SnapshotArray object will be instantiated and called as such:
31 * let obj SnapshotArray(length)
32 * obj.set(index, val)
33 * let ret_2: Int obj.snap()
34 * let ret_3: Int obj.get(index, snap_id)
35 */ 转载于:https://www.cnblogs.com/strengthen/p/11297779.html
